Download Physical Sciences Grade 12 Term 2

Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
12
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2.
LESSON DEVELOPMENT:
TIMING
RESOURCES NEEDED
Learners answer the baseline
Learners take notes from the
board.
3.
Introduce the lesson with the baseline questions
Pre-knowledge

1
questions.
2.1 Introduction

Lesson
At the end of this lesson learners should know:

The meaning of Doppler effect
The following results will be the outcome of this lesson:

Learners must be able to state what the Doppler Effect is for sound and give everyday examples.

Learners must be able to explain why a sound increases in pitch when the source of the sound travels towards a listener and decreases in pitch it
travels away.

Learners must be able to describe applications of the Doppler Effect with ultrasound waves in medicines, e.g. to measure the rate of blood flow or
the heartbeat of foetus in the womb.
Question and answer, Explanation
2.
Doppler Effect
DATE COMPLETED:
TEACHER ACTIVITIES
1.
TOPIC
Learners write the classwork.
25 min
CLASSWORK
1. What is meant by the term
Frequency, relative velocity, pitch
Chalkboard for notes,
discussions and classwork
15 min
“Doppler Effect”?
BASELINE ASSESSMENT
10 min

Baseline questions
2. a) What principle can be applied

What is meant by the term frequency?
to explain what happens to the

Define relative velocity.
pitch of a sound as the source

What is the relationship between frequency and pitch?
come closer and closer, passes you
and moves away?
2.2 Main Body (Lesson presentation)

Lesson starts with the educator asking the learners the baseline questions.
b) Why does this happen?

Educator and learners discuss the following answers of the baseline assessment
c) Give a real life example.

Frequency is the number of complete waves passing a point in a second.

It is a point of origin or zero point with a set of directions.

The higher the frequency, the higher the pitch.
Term 2 Page 1
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

3. The apparent change in the
Educator explains and discusses with learners the following
frequency of a wave as a result of
The Doppler Effect and sound
The Doppler Effect is the apparent change in the frequency of a wave as a result of the
the relative motion between the
relative motion between the observer (listener) and the source.
observer and the source is called
In other words, it is an alteration in the observed frequency of a sound due to motion of
A. resonance
either the source or observer or both.
B. Doppler Effect

Although less familiar, this effect is easily noticed for a stationary source or observer.
C. Ultrasound

The Doppler Effect is experienced whenever the speed of the object making the sound is
D. sonic boom
slower than the sound waves it produces.
4. When a car approaches a

The Doppler Effect and sound: car approaches observer
stationary observer on the ground,

For example, when a car passes an observer on the ground, the observer notices that the
A. the observer notices that the
pitch of sound is higher.
pitch of the sound is lower.
The pitch of the sound is proportional to the frequency of the wave. The frequency of the
B. the observer notices that the
wave being produced is constant.
sound is louder.
As the object approaches the observer, the distance that the wave must fit into decreases,
C. the observer notices that the
so the wavelength becomes shorter to fit into the smaller distance.
pitch of the sound is higher.
Therefore he notices that the sound waves reach him at a more frequent rate, therefore
D. the observer notices that the
higher pitch.
sound is softer.

The Doppler Effect and sound: car moves away from an observer
SOLUTIONS

As the object moves past the observer and distance between him and object increases,
1. Doppler Effect is the apparent
the waves spread out and reach him at a less frequent rate, therefore lower pitch.
change in the frequency of a wave
The Doppler Effect is not a result of an actual change in frequency of the source. The
as a result of the relative motion
source puts out the same frequency, but the observer perceives it a different frequency.
between the observer (listener) and

The Doppler Effect also occurs when the source is at rest and the observer is moving.
the source.

If the observer is moving towards the source, the pitch is higher and if the observer is
2. a) Doppler Effect principle
moving away from the source, the pitch is lower.
b) If a source of sound of a

The Doppler Effect and Ultrasound
constant frequency is moving

Ultrasound refers to sound waves with a frequency above human hearing (greater than 20
towards an observer, the sound
kHz)
seems higher in pitch; whereas






when it moves away it seems lower.
Term 2 Page 2
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
The very high frequency that ultrasound has a small wavelength. Therefore it can be
c) It can be heard by an observer
reflected and refracted by very small objects.
listening to the whistle of a train

A large wavelength will pass over these small objects.
coming into a station etc.

Ultrasound reflects well off organs and tissue in the body. When the ultrasound is reflected
3. B
off an object, the reflected wave undergoes the Doppler Effect.
4. C


Sensitive instruments can determine the difference between the frequency of the outgoing
waves and the reflected waves.

The heartbeat and the flow of blood in an unborn baby are detected this way.

This technique is also used to locate underwater objects. This is called Sonar.
2.3 Conclusion

Ask learners about the main aspects of the lesson

Give learners classwork
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 3
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Term 2 Page 4
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
12
LESSON SUMMARY FOR: DATE STARTED:
TOPIC
Doppler Effect
Lesson
2
DATE COMPLETED:
At the end of this lesson learners should know:
The following results will be the outcome of this lesson:

Learners must be able to use the equation
LESSON OBJECTIVES
fL 
v  vL
fs
v  vs
to calculate the frequency of sound detected by a listener (L) when either the listener or the source (S) is moving.
TEACHER ACTIVITIES
LEARNER ACTIVITIES
1.
Learners answer the baseline questions.
Question and answer, Explanation
2.
Learners take notes from the board.
2.
3.
Learners write the classwork.
1.
TEACHING METHODS USED IN THIS LESSON
LESSON DEVELOPMENT:
CLASSWORK
2.1 Introduction

Introduce the lesson with the baseline questions
Use speed of sound in air as 340 m•s-1.
Pre-knowledge

TIMING
1.
Ambulance moving at 40 m•s-1 approaches a
traffic light where a blind man and his dog are
Frequency, velocity, conversion of the units

Baseline questions
ambulance transmits waves at a frequency of

In what units is frequency measured in?
350 Hz. The pitch of the sound decreases as

Convert 20 kHz to Hz.
the ambulance moves past the man and

Convert 72
5 min
Chalkboard for notes,
20 min
discussions and classwork
25 min
waiting to cross the road. The siren of the
BASELINE ASSESSMENT
km•h-1
RESOURCES NEEDED
to
drives further away from him. It is assumed that
m•s-1
the speed of sound in air is 340m•s-1.Determine
2.2 Main Body (Lesson presentation)

Lesson starts with the educator asking the learners the baseline questions.
the apparent frequency of the sound waves

Educator and learners discuss the following answers of the baseline assessment
that the man observes as the ambulance

Hertz (Hz)
approaches him.

20 kHz = 20 x 103 Hz

72 km•h-1 = 72/3,6 = 20 m•s-1

Educator explain and discuss with learners the following
Term 2 Page 5
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.
The Doppler Effect Equation

It is possible to calculate the frequency of the sound waves that the listener
railway crossing. It warns the pedestrians and
hears when the source and/or listener moves towards or away from each other
motorists waiting at the crossing, by
by using the following equation, known as the Doppler equation.
transmitting a siren at a frequency of 2000 Hz.
fL 
Calculate the frequency at the instant the
v  vL
fs
v  vs

The Doppler equation is:

Where: fL = frequency of sound heard by listener
pedestrians hear the sound as the train
approaches the railway crossing.

fS = frequency of sound emitted by the sound source

v = speed of sound in air

vS = speed of source

vL = speed of listener


A train moving at 180 km•h-1 approaches a
If the source and listener move towards each other:
3.
km•h-1. The frequency of the sound that the
car emits
v  vL
fL 
fs
v  vs
fL 
v  vL
fs
v  vs
Worked Example
the observer hears when the car approaches
him.
3.2 Calculate the frequency at which the
observer hears the sound at the instant the car
passes him.
3.3 Calculate the frequency at which the
observer hears the sound when the car moves
The siren of an ambulance emits waves at a frequency of 1000 Hz. Determine the
frequency of the sound heard by a stationary listener when the ambulance is

towards the listener at a speed of 15 m•s-1

away from the listener at a speed of 15 m•s-1
is 1250 Hz.
3.1 Calculate the frequency of sound waves that
If the source and listener moves away from each other:
moving:
A racing car approaches an observer at 180
away from him.
SOLUTIONS
1.
fL 
v  vL
fs
v  vs
fL 
340
350
340  40
= 396,67 Hz
Solutions
Term 2 Page 6
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
a)
fL 
fL 
v  vL
fs
v  vs
340
1000
340 15
2.
fL 
v  vL
fs
v  vs
fL 
340
2000
340  50
= 1046,15 Hz
b)
fL 
v  vL
fs
v  vs
340
fL 
1000
340  15
= 957,75 Hz
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork
= 2344,83 Hz
3.1
fL 
v  vL
fs
v  vs
fL 
340
1250
340  50
= 1465.52 Hz
3.2 1250 Hz
3.3
fL 
v  vL
fs
v  vs
fL 
340
1250
340  50
= 1089,74 Hz
Term 2 Page 7
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 8
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
12
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
TOPIC
Doppler Effect
Lesson
3
DATE COMPLETED:
At the end of this lesson learners should know:

The meaning of Doppler Effect
The following results will be the outcome of this lesson:

Learners must be able to use the equation
fL 
v  vL
fs
v  vs
to calculate the frequency of sound detected by a listener (L) when either the listener or the source (S) is moving.
TEACHER ACTIVITIES
1.
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2.
LESSON DEVELOPMENT:
Introduce the lesson with the baseline questions
EXERCISE)
10 min
Chalkboard for notes,
40 min
discussions and classwork
QUESTION 1
Doppler Effect Equation, Doppler Effect
1.1 Doppler Effect
BASELINE ASSESSMENT
1.2 Car approaching

Baseline questions

Define Doppler Effect.

Write the Doppler equation if the source and listener are move towards each other.

Write the Doppler equation if the source and listener are move towards each other.
2.2 Main Body (Lesson presentation)

Lesson starts with the educator asking the learners the baseline questions.

Educator and learners discuss the following answers of the baseline assessment

When the sound source or the listener is moving there will be a change in the frequency of
the sound. We hear the sound lower or higher than the source actually is.

Learners write the consolidation
SOLUTIONS (CONSOLIDATION
Pre-knowledge

Learners answer the baseline
exercise
2.1 Introduction

RESOURCES NEEDED
questions.
Question and answer, Explanation
2.
TIMING
Educator give learners the following Consolidation exercise on Doppler Effect Equation
Term 2 Page 9
fL 
v  vL
fs
v  vs
fL 
=
1.3.1
340
(420)
340 16
440 ,74 Hz
Smaller
than
1.3.2 Increases
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
QUESTION 1
QUESTION 2
The siren of a police car produces a sound of frequency 420 Hz. A man sitting next to the road
2.1 Doppler Effect
notices that the pitch of the sound changes as the car moves towards and then away from
2.2
him.
fL 
1.1 Write down the name of the above phenomenon.
1.2 Assume that the speed of sound in air is 340 m•s-1. Calculate the frequency of the sound of
1000 
the siren observed by the man, when the car is moving towards him at a speed of 16 m•s-1.
1.3 The police car moves away from the man at constant velocity, then slows down and finally
comes to rest.
1.3.1
How will the observed frequency compare with the original frequency of the siren
when the police car moves away from the man at constant velocity? Write only
GREATER THAN, SMALLER THAN or EQUAL TO.
1.3.2
How will the observed frequency change as the car slows down whilst moving away?
2.3 Higher than
QUESTION 3
3.1
fL 
QUESTION 2
fL 
The siren of a burglar alarm system has a frequency of 960 Hz. During a patrol, a security officer,
travelling in his car, hears the siren of the alarm of a house and approaches the house at
2.1 Name the phenomenon that explains the change in the observed frequency.
2.2 Calculate the speed at which the patrol car approaches the house. Use the speed of sound
in air as 340 m•s-1.
2.3 If the patrol car had approached the house at a higher speed, how would the detected
frequency have compared to the first observed frequency of 1000 Hz? Write down only HIGHER
340  vL
(960)
340  0
vL = 14,17 m•s-1
Write only INCREASES, DECREASES or REMAINS THE SAME.
constant velocity. A detector in his car registers the frequency of the sound as 1000 Hz.
v  vL
fs
v  vs
v  vL
fs
v  vs
1500
(250000)
1500  20
= 253,38 x 103 Hz
3.2 Remains the same
The detected frequency is
independent of the distance
between the source and the
observer.
THAN, LOWER THAN or EQUAL TO.
QUESTION 3
Dolphins use ultrasound to scan their environment.
When a dolphin is 100 m from a rock, it emits ultrasound waves of frequency 250 kHz whilst
swimming at 20 m•s-1 towards the rock. Assume the speed of sound in water is 1500 m•s-1.
Term 2 Page 10
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
3.1 Calculate the frequency of the sound waves detected by a detector on the rock.
QUESTION 4
3.2 When the dolphin is 50 m from the rock, another ultrasound wave of 250 kHz is emitted.
4.1 Doppler Effect
How will the frequency of the detected sound waves compare with the answer calculated in
4.2
QUESTION 3.1? Write down only HIGHER, LOWER or REMAINS THE SAME.
fL 
QUESTION 4
An ambulance with its siren on, moves away at constant velocity from a person standing next
90 / 100 fs 
to the road. The person measures a frequency which is 90% of the frequency of the sound
v  vL
fs
v  vs
340
( fs )
340  vs
vS = 37,78 m•s-1
emitted by the siren of the ambulance.
4.1 Name the phenomenon observed.
4.2 If the speed of sound in air is 340 m•s-1, calculate the speed of the ambulance.
QUESTION 5
5.1 Doppler Effect
QUESTION 5
5.2 Towards
The whistle of a train emits sound waves of frequency 2000 Hz. A stationary listener measures the
5.3
frequency of these emitted sound waves as 2080 Hz. The speed of sound in air is 340 m•s-1.
fL 
5.1 Name the phenomenon responsible for the observed change in frequency.
5.2 Is the train moving AWAY FROM or TOWARDS the stationary listener?
2080 
5.3 Calculate the speed of the train.
5.4 Will the frequency observed by a passenger, sitting in the train, be GREATER THAN, EQUAL
TO or SMALLER THAN 2000 Hz. Explain the answer.

Educator and learners discuss the questions and answers of the Consolidation Exercise.
2.3 Conclusion

Ask learners about the main aspects of the lesson.
v  vL
fs
v  vs
340
( 2000)
340  vs
vS = 13,08 m•s-1
5.4 Equal
The passenger moves at the same
velocity as the train. / There is no
difference in velocity of the
passenger relative to the train.
Term 2 Page 11
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 12
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
12
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2.
LESSON DEVELOPMENT:
3.
Introduce the lesson with the baseline questions
1.

What is meant by “spectrum of light”?

Which wavelength of light is reflected the most?

Which wavelength of light is reflected the least?
Learners take notes from the
Learners write the classwork.
5 min
30 min
How can the Doppler Effect be
used to measure the motion of
BASELINE ASSESSMENT
Baseline questions
RESOURCES NEEDED
Learners answer the baseline
CLASSWORK
Spectrum of light, frequency and wavelength

TIMING
board.
Pre-knowledge

4
questions.
2.1 Introduction

Lesson
At the end of this lesson learners should know:

The meaning of “redshifts”
The following results will be the outcome of this lesson:

Learners must be able to state that light from many stars is shifted towards the red, or longer wavelength/lower frequency, end of the spectrum.

Learners must be able apply the Doppler effect to these “redshifts” to conclude that most stars are moving away from Earth and therefore the
universe is expanding
Question and answer, Explanation
2.
Doppler Effect
DATE COMPLETED:
TEACHER ACTIVITIES
1.
TOPIC
Chalkboard for notes,
discussions and classwork
20 min
the Earth and a star?
2.
What does it mean to say we
live in an expanding universe?
3.
Red shift is used as evidence of
an expanding universe. How
2.2 Main Body (Lesson presentation)

Lesson starts with the educator asking the learners the baseline questions.
can this evidence be

Educator and learners discuss the following answers of the baseline assessment
explained by using the

A spectrum of light is the rainbow-like series of colours, produced by splitting light into its
spectrum lines of stars?
component colours.

Violet

Red

Educator explain and discuss with learners the following
Term 2 Page 13
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
4.
A small number of galaxies

The Doppler Effect and Light

The velocities of distant galaxies can be determined using the Doppler Effect.
have been found to be moving

Light from these galaxies has shifted towards the lower frequencies of light i.e. towards red
towards the Earth. If you were
light, because red light has the lowest frequency of all the colours of the spectrum making
able to analyse light waves
up white light.
from these galaxies, what

This shift is called the redshift and indicates that the galaxies are moving away from us.
would you expect to find?

The greater the frequency shift, the greater the velocity with which the galaxy is moving
Why?
5.
away from us.
What additional evidence is

The further the galaxy is, the faster it is moving.
there to support the Big Bang

This has led to the conclusion that the universe is expanding and that at one time the
theory?
universe must have been highly concentrated and then it exploded outwards.
6.
How does this theory explain

This is called big bang.
the evolution of the universe up

If the star is moving towards us, then the absorption lines are shifted to higher frequencies
to the present time?
towards the blue end of the spectrum, and we say the absorption lines are blue shifted.





7.
One possible future of the
If we compare the absorption spectrum of the star to the spectrum of our Sun, we can
universe is the Big Crunch.
observe the shift in the frequencies of the absorption lines.
What has to happen to cause
By examining the spectrum of a star we can determine whether it is moving away from or
this?
towards our solar system.
SOLUTIONS
Astronomers study absorption spectra that come from stars in the galaxy, and they have
1.
The lines in the spectrum of a
recording these for many years.
luminous body such as a star
In the late 1800s and early 1900s, astronomers noticed that the absorption spectra that
are similarly shifted towards the
were being recorded for many years are redshifted to lower frequencies.
violet if the distance between
This has led astronomers to conclude that the universe is expanding.
the star and the Earth is
decreasing and towards the
2.3 Conclusion

Ask learners about the main aspects of the lesson.
red if the distance is increasing.

Give learners classwork
By measuring the shift the
relative motion of the Earth
and the star can be
calculated.
Term 2 Page 14
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.
The spectrum observed was
shifted to the red. That means
all stars or galaxies are moving
away from earth making the
Universe bigger.
3.
The absorption spectrum that is
observed is red shifted. This red
shifting is because of the
Doppler Effect. The red
indicates lower frequencies
which mean these galaxies are
moving away from the earth.
4.
The absorption lines of these
galaxies are blue shifted. The
frequencies are higher. They
are moving towards the earth.
5.
The fact that the universe is
expanding.
6.
As it is expanding from nothing
to something.
7.
The universe will then have to
contract again.
Term 2 Page 15
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 16
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
13
TOPIC
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2.
LESSON DEVELOPMENT:
RESOURCES NEEDED
Learners answer the baseline
Learners take notes from the
board.
3.
Introduce the lesson with the baseline questions
Pre-knowledge

TIMING
questions.
2.1 Introduction

1
At the end of this lesson learners should know:

The meaning of diffraction.
The following results will be the outcome of this lesson:

Learners must be able to define a wavefront as an imaginary line that connects waves that are in phase.

Learners must be able to define diffraction as the ability of a wave to spread out in wavefronts as they pass through a small aperture or around a
sharp edge.

Learners must be able to state Huygen’s Principle.
Question and answer, Explanation
2.
Lesson
DATE COMPLETED:
TEACHER ACTIVITIES
1.
2D and 3D wave fronts
30 min
Learners write the classwork.
1.
Chalkboard for notes,
discussions and classwork
CLASSWORK
Frequency, waves, period, wavelength
5 min
15 min
One word/term
BASELINE ASSESSMENT
a) The phenomenon observed

Baseline questions
when a wave bends around

What is meant by the term frequency?
the edges of an obstacle.

Define period.

Define wavelength.
b) The imaginary line joining points
in phase on a wave.
c) The principle which states that
2.2 Main Body (Lesson presentation)

Lesson starts with the educator asking the learners the baseline questions.
each point on a wave front

Educator and learners discuss the following answers of the baseline assessment
acts as a source of secondary

Frequency: number of cycles or complete waves formed in one second.
wavelets.

Period: time it takes for one complete wave to form.
2.
Define diffraction.

Wavelength: distance between any two consecutive points in phase.
3.
State Huygen’s principle.

Educator explain and discuss with learners the following:
Term 2 Page 17
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Diffraction patterns

4.
Diffraction is the bending of the waves that pass the edge of an obstacle or the bending of
waves as they go through a gap.

Which situation will show
greater diffraction and why?
a) A wavelength of 3 cm or a
This phenomenon is only found in waves and therefore any phenomenon that shows
wave of wavelength going
diffraction is a wave.
through the same narrow gap
or
b) The same wave passing
through a gap of 5 cm or 7 cm.
SOLUTIONS
1.
a) Diffraction
b) Wavefront
c) Huygen’s Principle
1.

The wavelength and size of the gap influences the amount of diffraction.

The smaller the width of the gap, the greater the diffraction i.e.

Diffraction patterns
Diffraction is the bending of the
waves that pass the edge of an
obstacle or the bending of
waves as they go through a
gap.
2.
Huygen’s principle states that
every point on a wavefront is a
source of a small wavelet that
spreads out and sends out a
secondary circular wavelet.
3.
a) The wave of wavelength 5 cm
will show greater diffraction as
it has a longer wavelength. The
longer the wavelength, the
greater the diffraction.
Term 2 Page 18
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
b) The smaller gap, 5 cm, will
show greater diffraction. The
smaller the gap, the greater the
diffraction.

The wavelength and size of the gap influences the amount of diffraction.

The smaller the width of the gap, the greater the diffraction i.e. diffraction is inversely
proportional to the width.

The longer the wavelength of the wave, the greater the amount of diffraction i.e.
diffraction is directly proportional to wavelength.

The maximum amount of diffraction occurs when circular waves are produced after the
waves pass through the gap and the wavelength is equal to the width of the gap.

The speed of the waves, however, does not change when the wave diffracts.

To explain why diffraction takes place, Huygen’s Principle is used.

It states that every point on a wave front is a source of a small wavelet that spreads out
and sends out a secondary circular wavelet.
Term 2 Page 19
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Huygens explains diffraction
Small circular wavelets are produced
by each point on the wavefront
Wavefronts

The small wavefronts that spread out from each point on a wave front form a new wave
front on the envelope of these secondary wave fronts.

When straight wavefronts pass the edge of a boundary they continue in the forward
direction.
Term 2 Page 20
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
•The wavelets starting at the edge of the
shadow region are able to spread out into the
shadow region because there are no other
wavefronts to interfere destructively and cancel
the sideways contribution.
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork.
Term 2 Page 21
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 22
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
WEEK
13
TOPIC
TEACHING METHODS USED IN THIS LESSON
LEARNER ACTIVITIES
1.
LESSON DEVELOPMENT:
Introduce the lesson with the baseline questions
Pre-knowledge

Interference, amplitude, wavelength, points in phase, standing waves
BASELINE ASSESSMENT
TIMING
RESOURCES NEEDED
Learners answer the baseline
questions.
2.
Learners take notes from the
10 min
Chalkboard for notes,
board.
2.1 Introduction

2
At the end of this lesson learners should know:

The meaning of interference
The following results will be the outcome of this lesson:

Learners must be able to define interference as when two waves pass through the same region of space at the same time, resulting in
superposition of waves.

Learners must be able to explain the concepts of constructive and destructive interference.

Learners must be able to predict areas of constructive and destructive interference from a diagram source material.

Learners must be able to investigate the interference of waves on the surface of water from two coherent sources, vibrating in phase.

Learners must be able to draw an interference pattern marking nodal lines and noting positions of maximum interference.
Question and answer, Explanation
2.
Lesson
DATE COMPLETED:
TEACHER ACTIVITIES
1.
2D and 3D wave fronts
3.
30 min
Learners write the classwork.
discussions and classwork
CLASSWORK
1.
Define the term interference.
2.
State the principle of
10 min
superposition.

Baseline questions

Define the following terms:
3.
o
Points in phase
a) a crest meets a crest
o
Wavelength
b) a crest meets a trough
o
Amplitude
c) a trough meets a trough
o
Transverse wave
4.
o
Constructive interference
a) Nodal lines
o
Destructive interference
b) Antinodal lines
What happens when
Define the following terms:
2.2 Main Body (Lesson presentation)

Lesson starts with the educator asking the learners the baseline questions.
Term 2 Page 23
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
5.
S1 and S2 are two coherent

Educator and learners discuss the following answers of the baseline assessment

Points in phase: the particles of the medium through which the waves move are in phase
point sources which are used to
when they move simultaneously in the same direction and with the same speed.
generate wavefronts to

Wavelength: distance between any two consecutive points in phase.
produce an interference

Amplitude: maximum displacements of the particles from the rest position.
pattern.

Transverse wave: a transverse wave is formed when the particles of the medium move
a) What is meant by coherent
perpendicular to the direction of propagation of the wave.

sources?
Constructive interference: when a crest meets a crest or trough meets trough in the same
b) If the distance between S1 and
medium, their amplitudes are added together to form a bigger crest or trough.
S2 is decreased, what is the

Destructive interference: when a crest meets a trough, their amplitudes are subtracted.
effect on the nodal lines?

Educator explain and discuss with learners the following
SOLUTION
1.
Interference and superposition
Interference occurs when

Interference occurs when pulses or waves cross each in the same space.
pulses or waves cross each

The displacements of the waves combine to form a new shape.
other in the same space.
2.
Principle of superposition: when
wave pulses cross, the
combined displacement is
equal to the algebraic sum of
Before meeting
their displacements.
Called:
Constructive
interference
3.
a) Constructive interference
b) Destructive interference
c) Constructive interference
Meeting
4.
a) Nodal lines are lines of zero
After meeting
disturbances caused by
destructive interference.
b) Antinodal lines are lines of

The Principle of Superposition is used to determine the size of the displacement.

It states that when wave pulses cross, the combined displacement is equal to the algebraic
maximum disturbance caused
sum of their displacements.
by constructive interference.
Term 2 Page 24
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

Standing waves are an example of interference.
5.

Nodes in a standing wave are points of destructive interference i.e. points of zero
a) Coherent sources are sources
displacement.
that are in phase (same

Antinodes are points of constructive interference i.e. points of maximum displacement.
frequency)

All of the above illustrate interference in one dimension.
b) The nodal lines in the pattern
decrease.
Interference in two dimensions

Interference in 2D is best illustrated using water waves.

When two circular waves are set up and these cross each other, interference takes place.

Patterns consisting of paths of zero disturbances, called nodal lines, are seen interspersed
with paths of maximum disturbance.

Nodal lines are lines of zero
disturbance caused by
destructive interference.
Antinodal lines are lines of
greater disturbance caused
by constructive interference.
(crest & trough)
2 crests or 2 troughs
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork.
Term 2 Page 25
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 26
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
13
TOPIC
2D and 3D wave fronts
Lesson
3
DATE COMPLETED:
At the end of this lesson learners should know:

The diffraction patterns
The following results will be the outcome of this lesson:

Learners must be able to sketch the diffraction pattern for a single slit.

Learners must be able to use sin 

m
a
for a slit of width a to calculate the position(angle from the horizontal) of the dark bands in a single slit diffraction pattern.
TEACHER ACTIVITIES
1.
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2.
LESSON DEVELOPMENT:
Learners answer the baseline
Learners take notes from the
board.
2.1 Introduction

RESOURCES NEEDED
questions.
Question and answer, Explanation
2.
TIMING
3.
Introduce the lesson with the baseline questions
Learners write the classwork.
Pre-knowledge
CLASSWORK

1.
Diffraction, interference
Chalkboard for notes,
10 min
30 min
Red light is shone through a single
BASELINE ASSESSMENT
slit onto a screen forming a

Baseline questions
diffraction pattern. Blue light is

Define diffraction
then shone through the same slit.

Define constructive interference
Compare the angle of the first

Define destructive interference
dark band in the red diffraction
15 min
2.2 Main Body (Lesson presentation)
pattern compared to the position

Lesson starts with the educator asking the learners the baseline questions.
in the blue diffraction pattern. The

Educator and learners discuss the following answers of the baseline assessment
wavelength of the red light is 700

Diffraction is the bending of waves around the edges of an obstacle or opening.
nm, while that of the blue light is

Constructive interference occurs when two pulses or waves meet crest to crest or trough to
450 nm. The width of the slit is 8 x
trough.
10-6.
Term 2 Page 27
discussions and classwork
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.
Find the position of the first dark

Destructive interference occurs when two pulses or waves meet peak to trough.

Educator explain and discuss with learners the following
band (first minimum) formed on

Diffraction of Light and Sound
the screen when blue light of

Sound waves are longer than light waves and therefore diffract more and are able to go
wavelength 460 nm and is passed
around corners.
through a slit with a width of 6 m.
3.
Determine the position of the first

Example: sound can be heard around corners.

Light waves are short and do not refract much.
dark band formed on the screen,

That is why we are unable to see around corners.
when red light of

Nevertheless, if the gap is small enough, light does diffract.
instead of blue light.

For example: if one looks at a light bulb through a stretched piece of cloth, the light source
4.
690 nm is used
How can you distinguish between
looks bigger than when you look at it without the cloth.
a single-slit diffraction pattern and

Single slit diffraction of light
a double slit interference pattern?

When light passes through a single narrow slit, the pattern similar to the one shown below is
5.
Monochromatic light with a
wavelength of 520 nm falls
seen
perpendicular onto a single slit, of
width 0,5 mm. A diffraction
pattern is seen on the screen.
SOLUTIONS
1.
Red: sin  = (m)/a

When monochromatic light is used, a broad, glowing, central light band is seen flanked by
darker lines.

=(1)(700 x 10-9)
8 x 10-9
If a narrower slit is used, the central band is narrower, as a great amount of diffraction is
 = 50
produced.

When the light is passed through the single slit, diffraction takes place at the edges of the
slit and according to Huygen’s Principle the edges of the slit act as point sources sending
out circular waves which interfere with each other.
Blue: sin  = (m)/a
= (1)(450 x10-9)
8 x10-6
 = 3,20
Term 2 Page 28
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.
sin  = (m)/a
sin  = (1)(460 x 10-9)
Single slit diffraction and interference
6 x 10-6
 = 4,39 0
3.
sin  = (m)/a
sin  = (1)(690 x 10-9)
6 x 10-6
 = 6,6 0
4.
Single- slit diffraction: one broad
central band with bands next to it
getting narrower and getting
fainter.
Double –slit diffraction: the
bands are all the same
thickness and the same


brightness.
Slit diffraction pattern can be calculated by using the equation
sin 

m
a
5.
sin  = (m)/a
sin  = (3)(520 x 10-9)
0,5 x 10-3
where a: width of the slit
 = 0,179 0
λ: wavelength of the light
m: the number of dark bands from the centre.
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork.
Term 2 Page 29
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 30
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
13
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
TOPIC
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2.
LESSON DEVELOPMENT:
3.
Introduce the lesson with the baseline questions
Learners answer the baseline
Learners write the consolidation
Learners and educator discuss
5 min
Chalkboard for notes,
SOLUTIONS( CONSOLIDATION
30 min
discussions and classwork
EXERCISE)
15 min
the consolidation exercise.
Diffraction, interference
BASELINE ASSESSMENT

Baseline questions
QUESTION 1

Define interference.
1.1 Each point on the wavefront

State Huygen’s Principle.
acts a source of spherical
secondary waves or wavelets
2.2 Main Body (Lesson presentation)
travelling away from source.

Lesson starts with the educator asking the learners the baseline questions.

Educator and learners discuss the following answers of the baseline assessment

Diffraction is the bending of the waves that pass the edge of an obstacle or the bending of
wavefront entering the slit acts
waves as they go through a gap.
as a source of secondary
Huygen’s principle states that every point on a wave front is a source of a small wavelet
wavelets. The wavelets
that spreads out and sends out a secondary circular wavelet.
propagate in all directions

Educator give learners the following Consolidation Exercise on 2D and 3D wave fronts
beyond the slit causing the

Consolidation Exercise
wave to spread into regions

RESOURCES NEEDED
exercise.
Pre-knowledge

TIMING
questions.
2.1 Introduction

4
At the end of this lesson learners should know:

The meaning of diffraction and interference.
The following results will be the outcome of this lesson:

Learners must be able to apply knowledge on 2D and 3D wave fronts.
Question and answer, Explanation
2.
Lesson
DATE COMPLETED:
TEACHER ACTIVITIES
1.
2D and 3D wave fronts
1.2 Each point on the initial plane
QUESTION 1
beyond those in line with the
Huygen’s principle is used to explain the wave phenomena, interference and diffraction.
slit.
Term 2 Page 31
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
1.3
1.1 State Huygen’s principle.
1.2 Use Huygen’s principle to explain the diffraction of water waves in a ripple tank as they
sin 
pass through a narrow opening in a barrier.
1.3 A single slit of unknown width is illuminated with red light of wavelength 650 nm. Calculate

m
a
sin 150 = (1)(650 x 10-9)/a
the width of the slit for which the first dark band will appear at 150.
 a = 2,7 x 10 -6 m
QUESTION 2
Light of a single frequency pass through a single slit. The first minimum is observed at point P on
a screen, as shown in the diagram below. Point O is the midpoint of the central bright band.
The distance OP is 2,5 cm and the slit width is 3,2 x 10-5 m.
QUESTION 2
2.1 Wave nature
2.2 Wavefronts from the slit arrive at
point P out of phase and interfere
destructively.
Light
2.3
O
P
sin 
Q
2.1. What can be deduced about the nature of light from this observation?

m
a
sin  = (1)(600 x 10-9)/3,2 x10-5
2.2. Explain how the minimum is formed at point P.
2.3. If the wavelength of the incident light is 600 nm, calculate the distance Q between the
 = 1,070
screen and the slit.
Tan 1,07 =(2,5 x10-2)/Q
2.4. The original slit is now replaced by a second slit of different width, while the distance Q and
the wavelength of the incident light remain the same. Distance OP changes to 4 cm.
2.4.1. How does the slit width of the second slit compare to that of the first slit? Only write down
GREATER THAN, SMALLER THAN or EQUAL TO.
Q = 1,34 m
2.4.1 Smaller than
2.4.2If OP increases:
2.4.2. Explain your answer to QUESTION 2.4.1 without performing a calculation.
sin = increases because sin is
inversely proportional to a.
QUESTION 3
Learners perform an experiment with monochromatic light. They pass the light through a single
slit. The distance between the screen and the slit is kept constant. The diagram below
represents the pattern observed during the experiment
QUESTION 3
3.1 The ability of a wave to
bend/spread out as they pass
through a small
aperture/around a sharp edge.
Term 2 Page 32
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
3.2 sin  = (m)/a
KEY
sin 30 = (2)/0,02 x10-3
Dark band
 = 5,23 x 10-7 m
Bright band
3.3 Green. It has a shorter
wavelength than yellow light.
x
The slit has a width of 0,02 mm and the SECOND dark band is formed on the screen at an angle
of 30 from the centre of the slit.
3.1 Define the term diffraction.
3.2 Calculate the wavelength of this light.
3.3 The light is either green or red. Given that yellow light has a wavelength of 577 nm, which
colour is used. Give a reason for your answer.
3.4 Using the same light as in QUESTION 3.2, write down TWO experimental changes that can be
3.4 Increase the slit width.
Decrease the distance
between the screen and the
slit.
3.5 A central band of alternate
bright and dark bands of equal
width.
made to decrease the distance x in the diagram above.
3.5 Describe the pattern that will be observed if the single slit is now replaced with a double slit.

Educator and learner discuss the solutions of the consolidation exercise.
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork.
Term 2 Page 33
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 34
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
15
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
TOPIC
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2.
LESSON DEVELOPMENT:
RESOURCES NEEDED
Learners answer the baseline
Learners take notes from the
board.
Introduce the lesson with the baseline questions
Pre-knowledge

TIMING
questions.
2.1 Introduction

1
At the end of this lesson learners should know:

The ways of measuring rates of reaction.
The following results will be the outcome of this lesson:

Learners must be able to suggest suitable experimental techniques for measuring the rate of a given reaction including the measuring of gas
volumes, turbidity, change of colour and the change of the mass of the reaction vessel.
Question and answer, Explanation
2.
Lesson
DATE COMPLETED:
TEACHER ACTIVITIES
1.
Rates and Extent of Reactions
3.
Learners write the classwork.
4.
Learners and educator discuss
the solutions to the classwork
Understanding of the parts of chemical equation, the writing and balancing of chemical
CLASSWORK
equations.
1.
BASELINE ASSESSMENT
Explain what is meant by the

Baseline questions
term “rate of reaction” and

Consider the hypothetical reaction:
how it can be measured.
2.
A (s) + B (l) → C (g) + D (aq)
Chalkboard for notes,
5 min
discussions and classwork
25 min
15 min
15 min
State in each of the following
explain what all the different parts of a chemical as shown.
reactions what change can
2.2 Main Body (Lesson presentation)
serve as indicator of reaction

Lesson starts with the educator asking the learners the baseline questions.
rate:

Educator and learners discuss the following answers of the baseline assessment

A and B: reactants

C and D: products

→: direction of reaction
solutions used to electroplate a

s, l, g, and aq: indicates the phase of the reactants and products
nickel bar.

Educator explain and discuss with learners the following:
a) Which one boils faster, tap
water or salt water?
b) Different concentration of silver
Term 2 Page 35
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
c) The reaction of iron nails with
Reaction rates
tap water and saltwater.

Reaction rate: indication of the chemical change that takes place in a certain time.

In the reaction

Zn (s) + H2SO4 (aq) → ZnSO4 (aq) + H2 (g)
various metals with

Rate of reaction can be expressed as
hydrochloric acid.

Amount of zinc used per minute (mass)

Amount of sulphuric acid per minute (mol)
concentrated nitric acid in an

Amount of zinc sulphate produced per minute (mol)
exothermic reaction. Some of

Volume of hydrogen produced per minute measured as reaction rate- change in the
the products that develop, are
concentration of the reactants or the products in a certain time interval.
NO2(g), a brown gas, and

Reaction rate = [products]/t or Reaction rate = [reactants]/t
copper(II) nitrate, which is a

The rate of reaction is the rate at which the [reactants] or the [products] changes
blue solution. Name four
d) Compare the reactivity of
3.
Copper shavings react with
different factors that can be
How concentration changes:
used as measure of reaction
reaction: X → Y:
Graph of concentration of
X against time.
rate.
Graph of concentration
of Y against time.
SOLUTION
[Y]
1.
[X]
The rate of reaction is the
A
speed of the reaction and it
B
can be measured as follows:
tA
the amount of reactant used
t
t
up per unit time or the amount
tB
of products formed per unit
time.
2.
a) Rate is measured as the time it
takes until large bubbles are
formed.
8
b) Rate measured as the time it
takes for the object to be
covered in zinc.
Term 2 Page 36
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
c) The time it takes for the object
The curve shows:

Reaction rate is not constant

Rate decreases with time

Rate of reaction = the tangent at a specific time

Rate of reaction at A is faster than at B
to rust.
d) Compare the rate at which
hydrogen gas is formed.
3.
a) Rate at which the brown gas is
formed measured with a gas
Change in concentration of reactants and the
products as the reaction continue.
syringe which has been sealed.
No Molecules
b) Rate at which the mass
decreases.
[ X]
[Y]
c) The rate at which copper is
being used up.
d) Change in colour
time (minutes)
•
•
e) Temperature increase
Rate of the reaction decreases when [reactants] decrease.
As reactants are used up, rate at which products are formed decreases.
Measurement of reaction rates:
•
Changes in colour
•
Change in temperature
•
Change in pH
•
Changes in volumes and mass
9
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork.

Educator and learners discuss the solutions of the classwork.
Term 2 Page 37
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 38
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
15
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2
TIMING
RESOURCES NEEDED
Learners answer the baseline
questions.
2.
LESSON DEVELOPMENT:
Learners take notes from the
board.
2.1 Introduction

Lesson
At the end of this lesson learners should know:

The meaning of rates of reaction and factors affecting rate.
The following results will be the outcome of this lesson:

Learners must be able to explain what is meant by reaction rate.

Learners must be able to list the factors which affect the rate of chemical reactions.

Learners must be able to explain in terms of the collision theory how the various factors affect the rate of chemical reactions.
Question and answer, Explanation
2.
Rates and Extent of Reactions
DATE COMPLETED:
TEACHER ACTIVITIES
1.
TOPIC
3.
Introduce the lesson with the baseline questions
Learners write the classwork.
5 min
Chalkboard for notes,
discussions and classwork
Pre-knowledge
CLASSWORK
30 min

1.
15 min
Kinetic Molecular Theory
The collision theory explains why
BASELINE ASSESSMENT
chemical reactions occur and

Baseline questions
why they take place at different

Define the rate of reaction.
rates. Give one term for each of
the following descriptions.
2.2 Main Body (Lesson presentation)
1.1 A chemical substance that

Lesson starts with the educator asking the learners the baseline questions.

Educator and learners discuss the following answers of the baseline assessment
speeds the rate of a chemical

The reaction rate is how fast/slow a reactions is.
reaction.

Educator explain and discuss with learners the following:
1.2 A collision in which the reacting
Factors affecting reaction rates
particles have sufficient kinetic

There are two catergories of reactions
energy and the correct

Homogenous where reactants and products are in the same phase
orientation.

Heterogeneous where reactants and products are in different phases.

In the case of homogenous reactions there are four factors that affect the reaction rate
Term 2 Page 39
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
1.3 The factor responsible for
1.
the nature of reactants
2.
concentration
increasing the rate of reaction
3.
the temperature and
when a solid is broken into
4.
the presence of a catalyst
smaller pieces.

In the case of heterogeneous reactions, there is a fifth factor, the surface area (state of
1.4 A measure of the average kinetic
energy of the particles in a gas.
division) affects the reaction rate.
2.
The Collision Theory
The rate at which
50 mm
For a chemical reaction to take place, atoms or molecules must get so close together
piece of clean magnesium
that their outer electrons energy levels overlap.
ribbon reacts with 20 cm3

Particles have to collide (come into contact with each other)
hydrochloric acid (concentration

Collisions must be effective
of 1mol•dm-3) is determined by

Particles must have enough kinetic energy to meet activation energy.
measuring the volume of

Particles must have correct orientation.
hydrogen gas released during

The Collision Theory and Factors affecting the rate of reaction
the reaction
State of division or surface area
Mg(s) + 2 HCl(aq) → MgCl2(aq) +

H2(g)
Breaking a solid into smaller pieces allow for more vigorously mixing of particles and more
freedom of movement
State how the rate of this

The greater the exposed surface area, the faster the reaction rate.
reaction will be influenced if the

This is because the number of collision increases and therefore more effective collisions
experiment is repeated three
The concentration of the reactants
times altering only ONE factor at

A higher concentration means a greater number of particles in a given volume.
a time as follows. (Simply state

If there are more particles, there will be more collisions and therefore more effective
INCREASE, DECREASE, or REMAIN
collisions.
THE SAME)

Hence the rate of reaction increases.
2.1 The 50 mm piece of magnesium
The temperature of the reactants

is filed to a powder.
The temperature of a system is a measure of the average kinetic energy of the particles in
2.2 20 cm3 of HCl of a 2mol•dm-3
that solution (B1 only in gases.

concentration is used.
If the average kinetic energy is increased by increasing the temperature, more particles
2.3 The mixture is cooled.
will have enough kinetic energy between themselves to collide successfully and react.
Term 2 Page 40
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

The rate of both exothermic and endothermic reactions will increase with an increase in
3.
temperature.
An iron nail will displace copper
metal from a solution of copper
The presence of a catalyst
sulphate. Give three ways in

A catalyst lowers the amount of energy needed for a successful collision.
which the rate of this reaction

In the presence of a catalyst more collisions are successful and the rate of both the
can be increased.
endothermic and exothermic reactions increases.

A catalyst lowers the activation energy and therefore more particles with sufficient
energy to break bonds, are available.
SOLUTIONS
2.3 Conclusion
1.

Ask learners about the main aspects of the lesson.
1.1 catalyst

Give learners classwork.
1.2 effective collision
1.3 surface area
1.4 temperature
2.
2.1 increase
2.2 decrease
2.3 decrease
3.
a) Use iron powder instead of the
nails.
b) Heat the reaction mixture.
c) Increase the concentration of the
CuSO4 solution.
Term 2 Page 41
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 42
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
15
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
TOPIC
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2.
LESSON DEVELOPMENT:
RESOURCES NEEDED
Learners answer the baseline
Learners take notes from the
board.
3.
Introduce the lesson with the baseline questions
Pre-knowledge

TIMING
questions.
2.1 Introduction

3
At the end of this lesson learners should know:

The mechanism of reaction and of catalysis.
The following results will be the outcome of this lesson:

Learners must be able to define activation energy.

Learners must be able to use graph showing the distribution of molecular energies to explain why only some molecules have enough energy to
react and hence how adding a catalyst and heating the reactants affects the rate.

Learners must be able to interpret the Maxwell Boltzmann curve.
Question and answer, Explanation
2.
Lesson
DATE COMPLETED:
TEACHER ACTIVITIES
1.
Rates and Extent of Reactions
10 min
Learners write the classwork.
30 min
CLASSWORK
1.
Exothermic and endothermic reaction, Activated complex, Concentration.
discussions and classwork
In endothermic reactions the
reactants
BASELINE ASSESSMENT
Chalkboard for notes,
10 min
A. have more energy than the

Baseline questions

Define exothermic reaction.

Define endothermic reaction.

Define activated complex.

Define concentration.

What is meant by H and why is H negative for an exothermic reaction and positive for an
products
B.
have less energy than the
products.
C. have the same energy as the
products.
D. are at a lower temperature
endothermic reaction?
than the products
2.
2.2 Main Body (Lesson presentation)
In an exothermic reaction

Lesson starts with the educator asking the learners the baseline questions.
A. H is positive

Educator and learners discuss the following answers of the baseline assessment
B.
Term 2 Page 43
the activation energy is always
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

C. there is a decrease in internal
in which there is a net release of energy.

more than the heat of reaction
Exothermic reaction: a reaction in which more energy is released than what is absorbed or
energy
Endothermic reaction: a reaction in which more energy is absorbed than what is released
or in which there is a net absorption of energy.
D. there is no energy change

Activated complex: is the energy required to initiate a chemical reaction.
3.

Concentration: is the amount of solute per unit volume of solution.
is added to a reaction mixture

H: is the net amount of energy absorbed or released during a chemical reaction. It is
to increase the reaction rate. A
negative for an exothermic because the energy of the products is less than the energy of
further characteristic of such a
the reactants. It is positive because the energy of the products is greater than the energy
catalyst, is that it
A. affects only endothermic
of the reactants.

reactions
Educator explain and discuss with learners the following:
B.
Mechanism of reaction and catalysis

A catalyst is a substance which
does not undergo any
permanent change
The steps that atoms go through as their arrangement changes from reactants to products
C. increases the reaction rate of
are known as the MECHANISM of the reaction.
redox reactions only

On the microscopic level a number of steps are essential before a reaction will occur.

The model used to explain the reaction mechanism is the collision theory.

The collision theory

Reacting atoms, molecules or ions must collide with each other.

The particles must have sufficient energy and must be oriented correctly.
collision theory to explain why

Bonds in the original molecules must break and new bonds must form.
chemical reactions need

Electrons must be re-arranged in order to form new bonds.
activation energy?
D. increases the reaction rate of
acid-base reactions only.
4.
5.
The activated complex

Use your knowledge of the
Explain how the activation
All reactions need energy to start. The reacting atoms must pass over an “energy hill” to
energy influences the overall
change from reactants to products.
reaction rate.

The transition state that atoms must pass through is called the ACTIVATED COMPLEX.

The activated complex is an unstable structure where bonds are forming and breaking at
energy” Rewrite this statement
the same time.
to be scientifically correct.

Energy diagrams showing the changes in the potential energy of the reacting substances
6.
7.
during the reaction.
“Catalysts lower the activation
How does a negative catalyst
influence reaction rate.
SOLUTIONS
Term 2 Page 44
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
1.
B
2.
C
3.
B
4.
Existing bonds must be broken
to enable the particles to
collide with the particles of the
other reactants. Energy is
needed to break existing
bonds between atoms.
5.
Reactions with lower activation
energy occur faster than
reactions with higher activation
energy.
6.
Catalysts provide alternative
routes that require less energy.
7.
Negative catalysts reduce
reaction rate.

In an exothermic reaction the energy of products is less than the energy of the reactants

In an endothermic reaction the energy of products is greater than the energy of the
reactants.

Activation energy (Ea): the difference in energy between the reactants and the activated
complex. Unit is kJ•mol-1

Activation energy is also referred to as the minimum amount of energy required for a
molecule to react.
Term 2 Page 45
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

Heat of reaction (H): the difference in energy between reactants and products. Unit:
kJ•mol-1.

H > 0 for an endothermic reaction

H  0 for an exothermic reaction.
The mechanism of a catalyst

The function of a catalyst is to provide an alternate route for the reaction to take place.

This route has lower activation energy and the rate of reaction increases.

A catalyst forms part of the activated complex and when this decomposes the catalyst is
released unchanged.

Two kinds of catalysis

Homogenous: the catalyst is the same phase as the reactants.

Heterogeneous: the catalyst in different phase as the reactants.

Catalysts cannot cause a reaction to occur; they can only affect the rate of the reaction.
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork.
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 46
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
15
TOPIC
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
TIMING
RESOURCES NEEDED
Learners answer the baseline
questions.
2.
LESSON DEVELOPMENT:
Learners write the consolidation
exercise.
2.1 Introduction

4
At the end of this lesson learners should know:

The factors affecting the rates of reactions.
The following results will be the outcome of this lesson:

Learners must be able to compare results.

Learners must be able to draw conclusions.

Learners must be able to apply knowledge.
Question and answer, Explanation
2.
Lesson
DATE COMPLETED:
TEACHER ACTIVITIES
1.
Rates and Extent of Reactions
3.
Introduce the lesson with the baseline questions
Learners and educator discuss
Pre-knowledge
the solutions of the

consolidation exercise.
Factors affecting reaction rates, Collision theory
BASELINE ASSESSMENT
SOLUTIONS

Baseline questions
QUESTION 1

List the factors affecting the reaction rate
1.1 Neutralisation reaction
1.2.1
2.2 Main Body (Lesson presentation)
Chalkboard for notes,
discussions and classwork
What is the relationship
Lesson starts with the educator asking the learners the baseline questions.
between temperature and

Educator and learners discuss the following answers of the baseline assessment:
the reaction rate of an

The nature of reactants
antacid tablet with water?

Concentration

The temperature
increase with increase in

The presence of a catalyst
temperature.

Surface area or state of division

Educator gives learners the consolidation exercise.
Term 2 Page 47
35 min
20 min

1.2.2
5 min
The reaction rate will
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
QUESTION 1
1.2.3
Antacids are used to relieve indigestion. Indigestion is the condition when the stomach

Use the measuring and
produces too much acid resulting in an uncomfortable and painful feeling. A certain antacid
measure a fixed volume of
tablet dissolves in water and reacts with the acid in the stomach to release carbon dioxide gas.
water and transfer it to the
1.1. Name the type of chemical reaction that explains why antacids bring relief from
beaker.
indigestion.

1.2. A group of learners wants to investigate the effect of temperature on the rate of dissolution
of this antacid tablet in water.
Record the temperature of the
water.

Add one antacid tablet to the
Design an investigation that the group of learners can conduct by answering the questions
water and measure the time it
below.
takes to dissolve.
1.2.1.
State an investigative question.
1.2.2.
State a hypothesis for this investigation.
and repeat the experiment at
1.2.3.
Write down a procedure that can be followed in this investigation to test your
two more different
hypothesis using some or all of the apparatus/chemicals listed below:
temperatures.

Rinse the solution down the sink

Thermometer

Stopwatch

Hot plate

Breaker
it will bring relieve will be faster

Measuring cylinder
at a higher temperature.

Spatula/Teaspoon
QUESTION 2

Water
2.1 Smaller than

Antacid tablet
2.2 Reaction rate increases with

Repeat the above steps for
accuracy
1.3
1.3. Is it better to take the antacid tablet with warm water or cold water? Give a reason for your
answer.
Warm water. The rate at which
increase in concentration.
2.3 To make a fair comparison/test
2.4 When Mg is used up, the
QUESTION 2
reaction will stop.
A group of learners use the reaction between hydrochloric acid and magnesium powder to
2.5.1 Remains the same
investigate one of the factors that influence the rate of a chemical reaction.
2.5.2 Increases
The reaction that takes place is:
Mg(s) + 2 HCl (aq)
MgCl2 (aq) + H2 (g)
Term 2 Page 48
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
The learners use apparatus and follow the method shown bellow to conduct the investigation.
QUESTION 3
Method –Experiment 1:
3.1 Reaction rate increases with an
Step 1: Place a spatula of magnesium powder in a conical flask and add 50 cm3 HC l (ag) of
increase in temperature
known concentration.
3.2 Sulphur dioxide
Step 2: Simultaneously start the stopwatch and close the flask with the rubber stopper
3.3 Concentration of sodium
containing the delivery tube.
thiosulphate
Step 3: Measure the volume of the H2(g) formed in the intervals of 20 seconds.
3.4 Sulphur or S
Method – Experiment 2:
Repeat steps 1 to 3 above, but use only 25
3.5 Different people have different
cm3 of
the same HC (aq) diluted to 50
cm3
with
sight abilities/reaction times.
distilled water.
2.1 How does the concentration of the acid used in Experiment 2 differ from the concentration
of the acid used in Experiment 1? Write down only GREATER THAN, SMALLER THAN or EQUAL TO.
2.2 Write down a hypothesis for this investigation.
2.3 Why should the learners ensure that equal amounts of magnesium powder are used in each
of two experiments?
2.4 The learners use an excess HC l (aq) for the two experiments. Give a reason why the excess
will not influence the results
2.5 How will an increase in the temperature influence the following:
2.5.1 Final volume of gas obtained in each experiment
(write down only INCREASE, DECREASE or REMAINS THE SAME)
2.5.2 Volume of gas obtained each experiment after 40 s
(Write down only INCREASE, DECREASE or REMAINS THE SAME.)
QUESTION 3
Learners use hydrochloric acid and a sodium thiosulphate (Na2S2O3) solution to investigate the
relationship between rate of reaction and temperature. The reaction that takes place is
represented by the following equation:
Na2S2O3(aq)→ 2NaCl(aq) + S(s) + H2O(l) + SO2(g)
They add 5 cm3 dilute hydrochloric acid solution to 50 cm3 sodium thiosulphate solution in a
flask placed over a cross drawn on a sheet of white paper. The temperature of the mixture is
30 oC.
Term 2 Page 49
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
They measure the time it takes for the cross to become invisible. The experiment is repeated
with the temperature of the mixture at 40 oC, 50 oC and 60 oC respectively.
3.1 Write down a possible hypothesis for this investigation.
3.2 Write down the NAME of the product that requires the need to work in well-ventilated room.
3.3 Apart from the volume of the reactants, state ONE other variable that must be kept
constant during this investigation.
3.4 Write down the NAME or FORMULA of the product that causes the cross to become invisible.
3.5 Why is it advisable that the same learner observes the time that it takes for the cross to
become invisible?
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Educator and learners discuss the solutions of the consolidation exercise.
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 50
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
16
TOPIC
LEARNER ACTIVITIES
Learners answer the baseline questions.
Question and answer, Explanation
2.
Learners take notes from the board.
2.
3.
Learners write the classwork.
TEACHING METHODS USED IN THIS LESSON
LESSON DEVELOPMENT:
2.1 Introduction
CLASSWORK

1.
What does it mean when a reaction is reversible?
2.
Explain what the difference is between an open
Introduce the lesson with the baseline questions
Pre-knowledge
system and a close system. Which of the following
Rates of reaction
reaction(s) should occur in a closed system?
BASELINE ASSESSMENT

Baseline questions
( i) HCl (aq) + NaOH (aq) → NaCl (aq) + H2O (l)

List the factors that affect the rate of reaction
(ii) NH4Cl (g) ⇌ NH3 (g) + HCl (g)
2.2 Main Body (Lesson presentation)
(iii) 2Cu (s) + O2 (g) → 2CuO (s)

3.
Lesson starts with the educator asking the learners the baseline
TIMING
5 min
30 min
RESOURCES NEEDED
Chalkboard for notes,
discussions and classwork
15 min
A saturated solution of sodium chloride in water is
questions.
prepared. NaCl is dissolved in water until a small
Educator and learners discuss the following answers of the baseline
amount remains at the bottom. The following
assessment:
dynamic equilibrium reaction applies.

Surface area
NaCl (aq) ⇌ Na+ (aq) + Cl- (aq)

Concentration or pressure

Temperature

1
At the end of this lesson learners should know:

The meaning of chemical equilibrium and the factors affecting equilibrium
The following results will be the outcome of this lesson:

Learners must be able to explain what is meant by:
o Open and closed system.
o A reversible reaction.
o Dynamic equilibrium.

Learners must be able to list the factors which influence the position of an equilibrium.
1.

Lesson
DATE COMPLETED:
TEACHER ACTIVITIES
1.
Chemical equilibrium
3.1 What is the meaning of the double arrows in the
reaction?
Term 2 Page 51
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

Addition of a catalyst
3.2 Explain what is meant by “dynamic equilibrium”?

Nature of reactants
3.3 Compare the concentration of the sodium ion and

Educator explain and discuss with learners the following:
the chloride ion at equilibrium.
Open and closed system
3.4 How do you know the equilibrium has been reached?

Open system: matter enters or leaves the system.
SOLUTIONS

Closed system: covered, no particles enter or leave the system.
1.

Static equilibrium: reaction stops – no further change.
means that the products can break down and return

Dynamic equilibrium: two opposing reactions occur simultaneously
to the starting reactants.
and at a same rate, no visible change.
2.
Reversible reactions can go in both directions. This
A closed system is one in which no substances in the

Dynamic phase equilibrium:
reaction can escape, where an open system

Rate of evaporation = Rate of condensation
substances especially gases escape. Reaction (ii)

The equilibrium is represented by ⇌
should occur in a closed system.

Liquid ⇌ Vapour
3.

H2O(l) ⇌ H2O (g)
3.1 Double arrow: dynamic equilibrium has been

Graph of reaction rate
reached.
3.2 Two opposing reactions happen simultaneously and
at a same rate, thus equally so fast that no external
Evaporation
Reactionrate
Equilibrium
changes can be noticed.
3.3 [Na+] = [Cl-]
3.4 The amount of NaCl not dissolved at the bottom
Condensation
remains the same.
Time

Initially evaporation rate is faster than condensation rate.

Condensation rate picks up – evaporation rate declines

Horizontal line indicates where evaporation and condensation occur
at the same rate – dynamic phase equilibrium.
Reversible reactions

Many chemical reactions are reversible in closed systems.
Term 2 Page 52
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

Reversible reactions that do not go to completion and occur in both
the forward and reverse direction. Where the reactants form
products that in turn react together to give the reactants back.

As [reactants] decrease, the tempo forwards also decreases

H2 (g) + I2 (g) ⇌ 2HI (g)

Hydrogen and iodine react to form hydrogen iodide.

Hydrogen iodide is not very stable

Dissociates back into hydrogen and iodine.

Reversible reaction is represented by ⇌

The curve below: the change in reaction rate of the two reactions.
Reaction rate vs. time
Forward reaction
Reaction rate
Ewewig toestand
Backward reaction
Time

Forward reaction is initially fast; but slows down as more products are
formed.

The reverse reaction starts at a tempo of zero but speeds up as more
products are formed.

Two opposing reactions at the same rate – equilibrium.

When the reaction reaches equilibrium, the rate of the forward
reaction is equal to the rate of the reverse reaction.

Also, when equilibrium is reached the concentration of the reactants
and the products remain constant.

This is called dynamic equilibrium.
Term 2 Page 53
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork.
Reflection/notes:
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 54
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
16
TOPIC
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2.
LESSON DEVELOPMENT:
Learners answer the baseline
Introduce the lesson with the baseline questions
Pre-knowledge
Learners take notes from the
3.
Learners write the exercise
4.
Learners and educator discuss
5 min
15 min
5.
BASELINE ASSESSMENT
Chalkboard for notes,
discussions and classwork
5 min
Learners write the classwork.

Baseline questions
CLASSWORK

Consider the following reaction:
1.
;
15 min
the solutions of the exercise.
Chemical equilibrium and factors affection equilibrium
N2(g) + 3H2 (g) ⇌ 2NH3 (g)
RESOURCES NEEDED
board.
2.1 Introduction

TIMING
questions.
Question and answer, Explanation

2
DATE COMPLETED:
TEACHER ACTIVITIES
2.
Lesson
At the end of this lesson learners should know:

The meaning of the equilibrium constant.
The following results will be the outcome of this lesson:

Learners must be able to list the factors affecting the equilibrium constant.

Learners must be able to write the expression of the equilibrium constant having been given the equation of the reaction.

Learners must be able to calculate the equilibrium constant.
LESSON OBJECTIVES
1.
Chemical Equilibrium
Consider the equation:
20 min
2NO2 (g) ⇌ N2O4 (g)
H0

What effect would an increase in temperature have on the above equilibrium?
The concentration of NO2 is found

Which concentration (products or reactants) will increase as you effect this change?
to be 0,013 mol•dm-3 and that of
N2O4 to be 0,035 mol•dm-3. When
2.2 Main Body (Lesson presentation)

Lesson starts with the educator asking the learners the baseline questions.
the reaction is at equilibrium

Educator and learners discuss the following answers of the baseline assessment
calculate Kc.

The equilibrium will favour the reverse reaction.

The concentration of the reactants will increase.

Educator explain and discuss with learners the following:
Term 2 Page 55
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.
The Equilibrium Constant (Kc)

For hypothetical reaction
are mixed in a closed
aA + bB ⇌ cC + dD

container and heated to 440
The equilibrium constant for this reaction:
oC.
reactants and products are as
[A]a[B]b




At equilibrium it is found
that the concentration of the
Kc = [C]c[D]d

Hydrogen gas and iodine gas
Kc values would be higher for a reaction equilibrium that lies far to the right i.e. if the
follows:
concentration of the products is higher.
[H2] = 2,06 mol•dm-3
Kc values would be lower for an equilibrium that lies far to the left i.e. if the concentration of
[I2] = 13,4 mol•dm-3
the reactants is higher.
[HI] = 36,98 mol•dm-3
The value of Kc is constant at a particular temperature i.e. temperature is the only factor
Calculate the equilibrium
that affects Kc.
constant at 440 oC
If the temperature is increased or decreased, Kc will change depending on which side the
H2 (g) + I2 (g) ⇌2HI (g)
equilibrium shifts according to Le Chatelier’s principle.
3.
For the reaction
For example if a change in temperature shifts the equilibrium to the right , the value of Kc
SO2 (g) + NO2 (g) ⇌ NO (g) + SO3 (g)
would increase.
the value of the Kc =4. The
If the reagent is a solid or liquid, its concentration is taken to be 1 and thus does not appear
concentrations at
in the Kc expression.
equilibrium are as follows:

Kc has no units.
[SO3] = 0,2 mol•dm-3

Educator gives learners the following class exercise.
[NO] = 0,4 mol•dm-3

Class exercise
[NO2] = 0,1 mol•dm-3
1.
Write down an expression for the equilibrium constant for each of the following reversible
Calculate the
reactions:
concentration of SO2.
1.1 2H2O2 (aq) ⇌ 2H2O (l) + O2 (g)
1.2 2HCl(aq) + CaCO3 (s) ⇌ CaCl2
4.
(aq)
+ H2O (l) + CO2 (g)
Carbon dioxide reacts with 36
g of graphite in a 1dm3 container.
1.3 N2 (g) + 3H2 (g) ⇌ 2NH3 (g)
At equilibrium it is found that there
2.
In which of the following reactions will the concentration at equilibrium of the products be
is 0,38 mol of carbon dioxide and
much higher than the reactants?
1,24 mol of carbon monoxide.
2.1 H2 (g) + F2 (g) ⇌ 2HF (g)
2.2 SO2 (g) + NO2 (g) ⇌ NO (g) + SO3 (g)
Kc = 1 x
108
Kc = 1 x
102
Calculate the value of the
equilibrium constant.
Term 2 Page 56
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.3 H2O (g) ⇌ 2H2 (g) + O2 (g)

Kc = 6 x 10 -28
Educator and learners discuss the following solutions of the class exercise.
1.
CO2 (g) + C (s) ⇌ 2CO (g)
SOLUTIONS
1.
1.1 Kc = [O2]
[NO2]2
[H2O2]2
= 0,035
1.2 Kc = [CO2][CaCl2]
(0,013)2
= 207,1
[HCl]2
1.3 Kc =
Kc = [N2O4]
[NH3]2
[N2][H2]3
2.
2.
Kc = [HI]2
[H2][I2]
2.1 [products] > [reactants]
= (36,98)2
2.2 [products] > [reactants]
(2,06)(13,4)
2.3 [products]  [reactants]
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork
= 49,54
3.
Kc = [NO][SO3]
[SO2][NO2]
4 = (0,4)(0,2)
[SO2](0,1)
[SO2] = 0,2 mol•dm-3
4.
c = n/v
[CO] =(1,24)/(1)
= 1,24 mol•dm-3
[CO2] = (0,38)/(1)
= 0,38 mol•dm-3
Kc = [CO]2
[CO2]
= (1,24)2
(0,38)
= 4,046
Term 2 Page 57
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 58
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
16
LESSON SUMMARY FOR: DATE STARTED:
TOPIC
Chemical Equilibrium
DATE COMPLETED:
TEACHER ACTIVITIES
LEARNER ACTIVITIES
1.
Learners answer the baseline questions.
Question and answer, Explanation
2.
Learners take notes from the board.
2.
3.
Learners write the classwork.
TEACHING METHODS USED IN THIS LESSON
LESSON DEVELOPMENT:
2.1 Introduction

Introduce the lesson with the baseline questions
5 min
1.
The following reaction reaches equilibrium at
25 min
30 oC in a closed
25 min
1 dm3container.
Dynamic equilibrium, Le Chatelier’s principle and factors affecting
H2 (g) + I2 (g) ⇌ 2HI (g)
equilibrium, Equilibrium constant, Stochiometry.
Calculate the value of Kc if 1 mol of H2 (g) and
Baseline questions
Consider the reaction:
RESOURCES NEEDED
Chalkboard for notes,
discussions and classwork
1 mol of I2 (g) are placed in the container and
BASELINE ASSESSMENT

TIMING
CLASSWORK
Pre-knowledge

3
At the end of this lesson learners should know:

The meaning of equilibrium constant.
The following results will be the outcome of this lesson:

Learners must be able to list the factors affecting the equilibrium constant.

Learners must be able to write the expression of the equilibrium constant having been given the equation of the reaction.

Learners must be able to calculate the equilibrium constant.

Learners must be able to explain the significance of high and low values of the equilibrium constant.
LESSON OBJECTIVES
1.
Lesson
analysis shows that 0, 8 mol of HI are present
2SO2 (g) + O2 (g) ⇌ 2SO3 (g)

What is the molar ratio of SO2 and O2?

What is the molar ration of O2 and SO3?
2.2 Main Body (Lesson presentation)
when equilibrium is reached.
2.
Reaction: PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)
0,375 mol of PCl5 (g) is heated in a closed 1
dm3 container. The equilibrium mixture

Lesson starts with the educator asking the learners the baseline questions.
contains 0,125 mol of chlorine. Calculate the

Educator and learners discuss the following answers of the baseline
equilibrium constant for the decomposition of
assessment:
PCl5.

2 mol of SO2 react with 1 mol of O2

1 mol of O2 produce 2 mol of SO3
Term 2 Page 59
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
3.
Nitric oxide (NO(g)) forms in internal

Educator explain and discuss with learners the following

Equilibrium Constant Calculations
combustion engines by the direct

Most calculations involving Kc you are given some information (usually the
combination of nitrogen and oxygen
number of moles) and asked to calculate the information not given and
according to the following reversible reaction
eventually Kc.
N2 (g) + O2 (g) ⇌ 2NO (g)

For such type of questions it helps to break the question as follows:
During a research experiment carried out by
o
START/INITIAL: here you record the moles of the starting substances (most
initially adding 1 mol of N2 and 1 mol O2 in a
products start at 0).
2 dm3 closed container at 300 K, it was found
CHANGE (Reacted/formed): “Reacted” applies to reactants and “formed”
that the concentration of the NO (g) present in
applies to products – molar ratios can be used in this step (not at start)
the container at equilibrium was 0,1 mol•dm-3.
EQUILIBRIUM: For reactants, this is moles at start minus the moles reacted
Calculate the equilibrium constant for the
(change). For products, this is moles at start plus moles formed (change)
reaction at this temperature.
o
o
o

EQUILIBRIUM CONCENTRATION: If the above values are in moles, then
SOLUTIONS
calculate the concentration using the formula c= n/v
1.
Example
H2
I2
HI
Initial (mol)
1
1
0
7 mol SO2 and 6 mol O2 put in a container of volume 2 dm3 at a temperature of
Change (mol)
0,4
0,4
0.8
600 K. At equilibrium 4 mol SO3 have formed. Determine the value of Kc.
Equilibrium (mol)
0,6
0,6
0,8
Solution
Concentration,
0,6
0,6
0,8
Reaction:
2SO2 (g) + O2 (g) ⇌ 2SO3 (g)
SO2
O2
SO3
c = n/v
Initial (mol)
7
6
0
(mol•dm-3)
Change (mol)
4
2
4
Equilibrium (mol)
7 -4 = 3
6 -2 = 4
4
Concentration , c=n/v
3/2 = 1,5
4/2 = 2
4/2 = 2
(mol•dm-3)
Kc = [HI]2
[H2][I2]
= (0,8)2
= 1,78
(0,6)(0,6)
Kc = [SO3]2
[SO2]2[O2]
= (2)2/ (1,5)2(2) = 0,889
Term 2 Page 60
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork.
2.
PCl5
PCl3
Cl2
Initial (mol)
0,375
0
0
Change (mol)
0,125
0,125
0,125
Equilibrium (mol)
0,25
0,125
0,125
Concentration,
0,25
0,125
0,125
N2
O2
NO
Initial (mol)
1
1
0
Change (mol)
0,1
0,1
0,2
Equilibrium (mol)
0,9
0,9
0,2
Concentration,
0,45
0,45
0,1
c = n/v
(mol•dm-3)
Kc = [PCl3][Cl2]
[PCl5]
= (0,125)(0,125)
(0,25)
= 6,25 x 10-2
3.
c = n/v
(mol•dm-3)
First calculate moles at equilibrium.
n NO = cv = (0,1)(2) = 0,2 mol
Kc = [NO]2
[N2][O2]
= (0,1)2
Term 2 Page 61
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
(0,45)(0,45)
= 0,049
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 62
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Term 2 Page 63
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
17
TOPIC
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2.
LESSON DEVELOPMENT:
3.
Introduce the lesson with the baseline questions
Learners take notes from the
1.
35 min
List the factors which affect the
equilibrium.
BASELINE ASSESSMENT
5 min
Chalkboard for notes,
Learners write the classwork.
CLASSWORK
Reversible reactions, chemical equilibrium, endothermic and exothermic reactions.

Baseline questions
2.
State Le Chatelier’s principle.

Define the terms endothermic and exothermic reactions.
3.
Study the following equation

What does H 0 mean?
2CO (g) + O2 (g) ⇌ 2CO2 (g) H0

Consider the reaction:
N2 (g) + 3H2 (g) ⇌ 2NH3 (g)
RESOURCES NEEDED
Learners answer the baseline
board.
Pre-knowledge

TIMING
questions.
2.1 Introduction

1
At the end of this lesson learners should know:

The factors affecting the chemical equilibrium.

The Le Chatelier’s Principle.
The following results will be the outcome of this lesson:

Learners must be able to state Le Chatelier’s Principle.

Learners must be able to explain qualitatively, given appropriate data, the effects of changes of pressure, temperature, concentration and the use
of a catalyst on the amount of each substance in an equilibrium mixture.
Question and answer, Explanation
2.
Lesson
DATE COMPLETED:
TEACHER ACTIVITIES
1.
Chemical Equilibrium
discussions and classwork
15 min
Use Le Chatelier’s principle to
H 0
predict what effect the
o
Is the forward reaction exothermic or endothermic?
following changes will have on
o
Is the reverse reaction exothermic or endothermic?
the equilibrium.
3.1 increase in the concentration
of O2
2.2 Main Body (Lesson presentation)

Lesson starts with the educator asking the learners the baseline questions.
3.2 decrease in temperature

Educator and learners discuss the following answers of the baseline assessment
3.3 increase in pressure
Term 2 Page 64
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

Endothermic reactions are reactions that absorb heat.
3.4 addition of a catalyst

Exothermic reactions are reaction that release heat.
4.

H 0 means the reaction is exothermic.
2SO2 (g) + O2 (g) ⇌ 2SO3 (g) H0

Forward reaction is exothermic.
What can be done to promote

Reverse reaction is endothermic.
the formation of SO3?

Educator explain and discuss with learners the following
SOLUTIONS.
Factors affecting chemical equilibrium and Le Chatelier’s principle:

1.
Le Chatelier’s principle is used to explain the effect of factors affecting chemical
equilibrium.

2.
closed system is disturbed by
any of the conditions i.e concentration, temperature, volume or partial pressure, the
changing any of the conditions
equilibrium will shift in such a way as to cancel the effect of the change.
i.e concentration, temperature,
volume or partial pressure, the
Consider the following reaction in a closed system:
6H2O ⇌
Co(H2O)62+
blue
+
equilibrium will shift in such a
4Cl-
way as to cancel the affect of
the change.
red
If you add a little water to the blue solution, it turns red i.e. the forward reaction uses up the
2.1 The equilibrium will favour the
water.

forward reaction.
If you add concentrated HCl to the red solution, it turns blue i.e. the reverse reaction uses
2.2 The equilibrium will favour the
up the Cl- ions.
forward reaction.

Conclusion

When you increase the concentration of a substance on the left, the equilibrium will favour
2.3 The equilibrium will favour the
the forward reaction and;

forward reaction.
2.4 The equilibrium will not be
When you increase the concentration of a substance on the right, the equilibrium will
affected. The catalyst will
favour the reverse reaction.
increase the rate of both the
forward and reverse reactions.
Temperature

When the equilibrium in a
Le Chatelier’s principle: when the equilibrium in a closed system is disturbed by changing
CoCl2- +

Temperature; concentration;
pressure/volume.
Concentration

Consider the reaction
Consider the following reaction in a closed system
2NO2 (g) ⇌ N2O4 (g)
brown
H 0
3.

Increase the concentration of
O2, SO2
yellow

Term 2 Page 65
Withdraw SO3
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

If the mixture is heated, the gas goes dark brown i.e. the equilibrium will favour the reverse

reaction.
Increase the pressure of the
system

This is the direction of the endothermic reaction.

Cooling the mixture will make the colour lighter i.e. the reaction will favour the forward

Decrease the temperature
reaction.

This is the direction of the exothermic reaction.
Exothermic reactions release heat.


Conclusion

A decrease in temperature favours the exothermic reaction and an increase in
temperature favours the endothermic reaction.
Pressure

Consider the following reaction
2SO2 (g) + O2 (g) ⇌ 2SO3(g)
2mol
1mol
2mol

The left hand side has 3 mol of gas and the right hand side has 2 mol.

The 3 mol of gas exerts more pressure than 2 mol, therefore an increase in pressure will
make the equilibrium shift to the side that exerts the least pressure i.e. the right hand side.

Conclusion

An increase in pressure favours the side with fewer molecules and a decrease in pressure
favours the side with more molecules.
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork.
Term 2 Page 66
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 67
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
17
TOPIC
LEARNER ACTIVITIES
1.
TEACHING METHODS USED IN THIS LESSON
2.
LESSON DEVELOPMENT:
3.
Introduce the lesson with the baseline questions

Consider the reaction:
N2 (g) + 3H2 (g) ⇌ 2NH3 (g)
Learners write the classwork.
Educator to give learners an
activity on the application of
BASELINE ASSESSMENT
Baseline questions
Learners take notes from the
CLASSWORK
Reversible reactions, chemical equilibrium, endothermic and exothermic reactions.

RESOURCES NEEDED
Learners answer the baseline
board.
Pre-knowledge

TIMING
questions.
2.1 Introduction

2
At the end of this lesson learners should know:

The factors affecting the chemical equilibrium.

The Le Chatelier’s Principle.
The following results will be the outcome of this lesson:

Learners must be able to apply the rate equilibrium principles to important industrial applications.
Question and answer, Explanation
2.
Lesson
DATE COMPLETED:
TEACHER ACTIVITIES
1.
Chemical Equilibrium
equilibrium.
5 min
Chalkboard for notes,
35 min
discussions and classwork
15 min
H 0
o
Is the forward reaction exothermic or endothermic?
o
Is the reverse reaction exothermic or endothermic?
2.2 Main Body (Lesson presentation)

Lesson starts with the educator asking the learners the baseline questions.

Educator and learners discuss the following answers of the baseline assessment

Forward reaction is exothermic.

Reverse reaction is endothermic.

Educator explain and discuss with learners the following
Term 2 Page 68
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Application to important industrial processes

The Haber process- industrial preparation of ammonia
N2 (g) + 3H2 (g) ⇌ 2NH3 (g)
H= -92,4 kJ•mol-1
Conditions: 150 – 250 atm ; 300 oC – 550 oC

Problems of Haber process

Rate of reaction

Room temperature, reaction very slow.

Increasing the temperature will speed up the reaction rate.

Chemical equilibrium

Reaction where ammonia forms is exothermic.

Increasing temperature, decreases formation of ammonia.

Less ammonia will be produced.

Lower temperature will produce more ammonia but will decrease the reaction rate too
much.

Catalyst

Catalyst can be used to increase reaction rate.

Requires a temperature of 400 oC to be effective.

Pressure

High pressure favours forming ammonia.

Extreme conditions like 200 atm pose safety risk.

Cost to strengthen pipes, reaction vessels very high.

Optimised yields

N2 and H2 constantly added to vessel (concentration increased).

Equilibrium is cooled, temperature between 300 oC and 500 oC.

Pressurized to 20 atm.

Ammonia liquefied and drained (concentration decreased).

Temperature of reaction is fast enough, the yield of ammonia about 60% (You get less
ammonia but you get it quickly).
Term 2 Page 69
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

The contact process- industrial preparation of sulphuric acid

Critical step
2SO2 (g) + O2 (g) ⇌ 2SO3 (g)

Most economic conditions

Temperature = 450 oC and a modest pressure of 1 -2 atm.

Vanadium pentoxide (V2O5) is used as a catalyst.

Catalyst has no effect on amount of SO3 produced it only speeds up the reaction.
2.3 Conclusion

Ask learners about the main aspects of the lesson.

Give learners classwork.
Reflection/note
Name of Teacher
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 70
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
18
Electrochemical Reactions:
1. Definition of Cells, using oxidation and reductions
(electron (e-) transfer) and anode and cathode in
terms of the mentioned aspects
TOPIC
LESSON
o

LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
The galvanic Cell:
Self sustaining electrode reactions
Conversion of electrical energy into chemical
energy
DATE COMPLETED:
1.
Learners will be TAUGHT and LEARN the following:

To define the galvanic cell in terms:
o
Self sustaining electrode reactions
o
Conversion of chemical energy to electrical energy
2.
LESSON OUTCOMES – At the end of the lesson learners should be able to:

define what is galvanic cell, using oxidation and reduction (electron (e-) transfer)

explain oxidation and reduction in terms of electrons transfer.

describe when the substance is oxidised and when the substance is reduced.

describe galvanic cell as self sustaining electrode reactions

understand conversion of electrical energy into chemical energy
TEACHER ACTIVITIES
1.
1 (a)
TEACHING METHODS USED IN THIS LESSON:
Explanations, illustrations, Demonstrations and questions and answer
methods
LEARNER ACTIVITIES
TIMING
RESOURCES
NEEDED
1. Baseline Assessment:
1. Write down and balance the reaction in which magnesium
combines with oxygen.
2Mg
+
O2
→ 2MgO
Term 2 Page 71
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.
Lesson Development
2.1 Introduction

The teacher will introduce the lesson by giving learners baseline
assessment.
OR

Using question and answer method?

Define the concept oxidation?

Define the concept reduction?

What is the reaction in which oxidation and reduction happen
simultaneously?

What energy conversion takes place in galvanic cell?

How does redox reaction differ with acids and bases?
1.1 Which element donates electrons and the element that
accepts the electrons? Refer to a periodic table in which
these elements are found.
1.2 Write down and balance the reactions in which
magnesium combine with Chlorine.
Mg
+
Cl2
→
MgCl2
1.3 Which element donates electrons and which element is
accepting the electrons?

Facilitate group discussion/ Response from the above assessment
activities.
2.1 Define each of the following expressions in terms of
electron transfer:

Explain: oxidation reaction in terms of metals reacting with
oxygen – (as previously described).

Demonstrate the process – using the periodic table

2.1.1
Oxidation: is the process by which electrons are
donated from one substance to another.
2.1.2
Reduction: is the process by which one substance
accepts electrons from another substance.
2.1.3
Lesson development
(learners will respond to questions)
Chalkboard
summary
± ( 15 min)
GROUP WORK ACTIVITY
Learners will work in groups to find solutions:
3.1 Contextualization questions:
Feedback: provide
correct answers
Magnesium donates electrons and chlorine accepts
electrons.
Discussion and Explanation Method (the teacher will clear any
misconceptions that the learners may have)
3.
Worksheet
± ( 15 min)
Magnesium is found in group 2 of the periodic table and
oxygen in 6.
2.
Use Lewis structure to explain the transfer of electrons
Baseline assessment:
Magnesium donates electrons and Oxygen accepts
electrons.
2.1.4
Oxidizing agent: A substance that removes electrons
from another reactant in a redox reaction. It is
reduced.
Reducing agent: A substance that donates electrons
to another reactant in a redox reaction. It is
oxidized.
Demonstration and
Explanation
Charts/ or
available
resources
± 15 minutes
OR
What reaction result when a metal rusts?
Term 2 Page 72
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

What is the essential difference between acid-base reactions and
redox reactions?
The teacher will then explain if these reactions: spontaneous or / nonspontaneous

Reactions of metals combining with oxygen were previously
called oxidation.

The term oxidation was used to describe the process in which an
element combines with oxygen.

In this reaction:
Mg (s) + O2 (g)



→ MgO2
These two oppositely charged ions now attract each other on
account of the strong electrostatic force which exists between
them.
Use Lewis structure/ Coupers notations to describe how electrons
are transferred to form metal oxide. (add two dots to complete
valency)
The oxidation process thus involves the transfer of electrons.
DEMONSTRATION USING PERIODIC TABLE:
Now consider the reaction of magnesium with chlorine:
+
2[Cl-]
Illustrations and
Explanation
Transfer of electrons from one substance to another
substance.
± 15 – 20 minutes
Relevant
equipments/ or
other available
resources.
Lesson Demonstration
and explanations
Chalkboard
summary
Select the correct word from those given in brakets:
Magnesium oxide is an ionic compound which is formed by each
magnesium atom losing its two valence electrons to the oxygen
atom, so forming Mg2+ and O2- ions.
Mg2+
Explain the concept redox reaction:
HOMEWORK
Mg:
+
꞉O꞉
Mg2+
+
[꞉O꞉]2- → MgO
 During this oxidation process, magnesium was the donor of
electrons, and oxygen the acceptor of electrons.

2.1.5
→
MgCl2
1.1 Reduction is the (gain / loss ) of electrons
1.2 Oxidation is the (loss / gain ) of electrons
1.3 Reduction occurs at the (anode/ cathode).
1.4 Oxidation occurs at the (anode/ cathode).
1.5 Magnesium metal is written as [Mg/ Mg2+ (aq)].
1.6 Magnesium ion is written as [Mg/ Mg2+ (aq)].
Provide one word
1.7 What do we call a device that makes use of
electrochemical reactions? Electrochemical cell
1.8 Write down two half cell reactions which occurs between
Magnesium and Oxygen
½ O2 (aq)
± 15 minutes
Mg2+ (aq) + 2 e-
Mg (s)
+ 2 e-
O 2-
(g)
1.9 Write down a total or nett cell reaction.
Term 2 Page 73
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

If we were to apply the original definition, this reaction could not
be classified as an oxidation reaction because it does not involve
the combination of oxygen with another substance.

Magnesium donate two electrons to the chlorine atoms

This change can be represented as follows:
+ 2eMg
→ Mg 2+
O2
+ 2e→ O 2 It is therefore necessary to consider oxidation not in terms of a
reaction with oxygen, but rather in terms of the electrons transfer
which takes place.

An oxidation process is therefore defined as the process by which
electrons are transferred from one substance to another.

Transfer of electrons implies that one substance must donate the
electrons and another must receive the electrons.
Mg (s)
Mg2+ (aq) + 2 e-
½ O2 (aq) + 2 eO 2-(g)
__________________________________
Mg (s)
+
½ O2 (g) →
Mg2+ (aq) +
1.9 For each of the following reactions write the oxidation
and reduction half-reactions. In each case name the
oxidizing agent and the reducing agent
a) Mg + Cu2+
→ Mg2+ + Cu
Answers: (a) Oxidation half - reaction:
Mg (s) →
Mg2+ (aq) +
2e-
Reduction half reaction:
Cu2+ (aq) + 2e-
→
Cu (s)

A substance that removes electrons from another reactant in a
redox reaction is reduced.

The process is known as oxidation

The substance that donates electrons to another reactant in a
redox reaction is oxidized.
Answer: (b) Oxidation half – reaction
The process is known as reduction.
Pb

O2- (g)
Oxidizing agent: Cu2+ ions
Reducing agent: Mg atom
b) 2Fe3+ Pb →
(s) →
2Fe2+ + Pb2+
Pb2+ (aq) +
2e-
Reduction half reaction:
4.
Lesson Development:
Fe3+ (aq) +
e-
→
Fe2+ (aq)
TEACHING – ACTIVITY
Oxidizing agent: Fe3+ ions
Use standard electrode potentials (reduction potentials) to explain
half cell reactions in terms of electron transfer
Reducing agent: Pb atom
Term 2 Page 74
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
+
−
⇌
Li
− 3,05
+
−
⇌
K
− 2,93
⇌
Cs
− 2,92
⇌
Ba
− 2,90
⇌
Sr
− 2,89
⇌
Ca
− 2,87
⇌
Na
− 2,71
⇌
Mg
− 2,36
⇌
Aℓ
− 1,66
⇌
Mn
− 1,18
Li + e
K +e
+
−
Cs + e
2+
−
Ba + 2e
2+
−
Sr + 2e
2+
−
Ca + 2e
+
−
Na + e
2+
−
Mg + 2e
3+
−
Aℓ + 3e
2+
−
Mn + 2e
2+
−
⇌
Cr
− 0,91
Cr + 2e
LESSON SUMMARYCONCLUSION:

Oxidation and Reduction occurs simultaneously.

The two reactions are known as half-reactions.
Reflection/note
Name of Teacher
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 75
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
GRADE
12
SUBJECT
Physical Sciences
WEEK
18
TOPIC
Electrochemical Reactions:
1. Definition of Cells, using oxidation and reductions
(electron (e-) transfer) and anode and cathode in terms
of the mentioned aspects
LESSON
o

LESSON SUMMARY FOR: DATE STARTED:
1.
1 (b)
The galvanic Cell:
Self sustaining electrode reactions
Conversion of electrical energy into chemical
energy
DATE COMPLETED:
Learners will be TAUGHT and LEARN the following:
To define the galvanic cell in terms:
LESSON OBJECTIVES
o
Definition of Redox Reaction – in relation to electron (e-) transfer.
o
The importance redox reactions in relation to energy conversion.
o
The application of these reactions in electrochemical cell of torch cells, car battery, etc.
2.
LESSON OUTCOMES – At the end of the lesson learners should be able to:

define what is galvanic cell, using oxidation and reduction (electron (e-) transfer)

explain oxidation and reduction in terms of electrons transfer.

describe when the substance is anode and when the substance is cathode.

describe galvanic cell as self sustaining electrode reactions

understand conversion of electrical energy into chemical energy
TEACHER ACTIVITIES
1. TEACHING METHODS USED IN THIS LESSON:
Explanations, illustrations, Demonstrations and questions and answer methods
LEARNER ACTIVITIES
TIMING
RESOURCES
NEEDED
Baseline Assessment:
One word question:
Term 2 Page 76
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2. Lesson Development
1.
The type of electrochemical cell in which
chemical energy is converted to electrical
energy.
Galvanic cell
2.
An ionic solution that conducts electricity.
Electrolyte solution
2.1 Introduction
a) Pre-knowledge required.

The teacher will introduce the lesson by giving learners baseline assessment.
3.

OR
Using question and answer method recap from previous knowledge?
The reactant that donates electrons during a
redox reaction. An anode

What do we call a process in which electrons are transferred?
4.

Why the solution of salt is called ionic?
Write down the half cell reactions in which
calcium reacts with sulphur.

A metal rod in which oxidation takes place?

Ca (s) → Ca2+ (aq) +
S (s) +
What energy conversion takes place in electrolytic cell?
2e- →
2e- - Oxidation reaction
S2- (aq)
- Reduction reaction
Baseline
assessment:
Worksheet
± ( 15 min)
Feedback:
provide correct
answers
Chalkboard
summary
± ( 15 min)
Discussion and Explanation Method (the teacher will clear any misconceptions that
the learners may have)

Facilitate group discussion/ Response from the above assessment activities.
1.

Explain the concepts:
Learners will work in groups to find solutions:
-
Anode and Cathode electrode
-
Reducing and Oxidizing agent
Identification of the precipitate formed during the
discoloration of the copper sulphate solution.
-
Galvanic cell
3.
Lesson development
1.1 Write down and balance a reaction of
Hydrochloric acid reacting with zinc, liberating
hydrogen. Show the phases of the substances.
Zn(s) + 2HCl(aq)
3.1 Contextualization questions:
The teacher will facilitate these question with the learners allow them to discuss their
solutions in class (± 10 minutes can be spend)

What type of energy exists in the electrolyte of car battery?
GROUP WORK ACTIVITY
→
ZnCl2(aq)
+
H2(g)
1.2 Write down the reaction of Nitric acid reacting
with copper. What is the colour solution?
3 Cu (s) + 8 HNO3 (aq) → 3 Cu(NO3)2 + 4 H2O + 2 NO
Term 2 Page 77
Demonstration
and Explanation
± 15 minutes
OR
Charts/ or
available
resources
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

Is this battery secondary cell or primary cell? Explain



Why such cells are said to be self sustaining electrode reactions?
What type of energy conversion takes place when this cell operates in a car?
What is the difference between concentrated solution and saturated solution?
DEMONSTRATION: (if there is enough resources – teacher can divide learners into
groups)
1.3 From the previous section, it appears that a
reaction occurs when zinc metal Zn (s) comes into
contact with copper ions
Cu2+ (aq).
However, if copper is placed in a solution
containing zinc ions
1.3.1
Is there any reaction taking place?
No reaction takes place.
To investigate the reaction between zinc metal and copper ions.
Prepare a dilute solution of copper sulphate by dissolving about 6g of copper
sulphate crystals (CuSO4.5H2O) in 250 cm3 of water.
1.3.2
Write down the equation which describes
your assumption.
Cu (s)
+
Zn2+ (aq) → no reaction
Zn
1.3.3
Not spontaneous, having to change external factors
to start the reaction.
Cu SO4 solution
1.3.4

What do you think is the cause of the blue colour of the solution?

Measure the mass of the zinc plate before is immersed in
1.3.5

After the zinc metal is placed in a solution do you notice any change?

If so, do you recognize the substance formed?

Do you notice any change in the intensity of the colour of the copper sulphate
solution?

If so, can you explain the change?
Find the new mass of the plate.
What has caused the change in mass?
Write down the equation that indicates
reaction between zinc metal when it comes
in contact with copper solution.
± 15 – 20
minutes
Relevant
equipments/ or
other available
resources.
Zn (s) + Cu2+ (aq) → Zn2+ (aq) + Cu (s)
the solution.


Is this reaction spontaneous or not
spontaneous explaining your answer?
Illustrations and
Explanation
Is this reaction spontaneous or non
spontaneous explain your answer?
Spontaneous reaction, takes place without having to
change any external factors to start the reaction
HOMEWORK
Since this sort of reaction finds wide application in a
study of electrochemical cells, it is important to know
which reactions between metals and metal ions
actually lead to spontaneous reactions.
In this connection, carry out the following investigation
Term 2 Page 78
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Discussion

The blue colour of the solution is caused by the presence of Cu2+ ions.

The increase in mass of the plate confirms that a substance (Copper) was
deposited on it.

The solution gradually becomes clear.

The Cu2+ ions which were in the solution precipitate out as Cu atoms, and the
blue colour of the disappears.
Practical Investigation:
Prepare dilute solutions (of concentration
approximately 0, 1 mol.dm-3) of the following salts.
The reaction can be represented as follows:
Cu2+ (aq)
Zn (s)
Cu2+ (aq)


+
+
ZnSO4 ; FeSO4 ; CuSO4 ; Pb(NO3)2 ; MgSO4 ; AgNO3
2e- → Cu (s)
----------------------- (1)
→ Zn2+ (aq) + 2e- -------------------- (2)
Zn (s)
→ Zn2+ (aq)
+
Now use the pieces of the metals Zn, Fe, Cu, Pb, Mg
and Ag.
Cu (s) ------------ (3)
Half – reaction (1) shows the reduction process. Copper ions receive electrons
and are reduced to copper atoms which are deposited on the zinc.
Half – reaction (2) shows the oxidation process during which zinc atoms act as
electron donors, are oxidized to zinc ions and thus go into solution.

By once again adding the two half-reactions together, equation

(3) results, which represents the complete reaction.

During the process electrons are thus transferred from the zinc atoms to the
copper ions.
Test which metals give spontaneous reactions with the
salt solutions.
Lesson
Demonstration
Remember after each test to clean the metal, and to
use a fresh portion of the salt solution for each test.
± 15 minutes
Chalkboard
summary
Write equations for the half – reactions and the
complete reaction for each spontaneous
reaction which occurs.
Learners will work in groups to find solutions:
Solutions to this practical will be presented by groups
to class.
TEACHING – ACTIVITY
HCl – is a compound which is broken into H+ and ClHCl (aq)
→
H+ (aq)
+
Cl- (aq)
Term 2 Page 79
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
REDOX REACTION
Oxidation:
Reduction:
Mg
(s)
2 H+ (aq)
→
+
2 e-
Mg2+
→
(aq)
+
2 e-
H2 (g)
CONCLUSION:

A reducing agent is a substance which, during a reaction, acts as an electron
donor and is oxidised in the process.

A oxidizing agent is a substance which, during a reaction, acts as an electron
receiver and is reduced in the process.

Redox reactions are characterised by the transfer of electrons.

Metal elements are mostly oxidised when reacting with non-metals.
The teacher will then explain if these reactions spontaneous or / non-spontaneous
Reflection/note
Name of Teacher
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 80
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Electrochemical Reactions: (Lesson 1C)
GRADE
12
SUBJECT
Physical Sciences
LESSON SUMMARY FOR: DATE STARTED:
1.
WEEK
18
o

TOPIC
Follow up from previous lesson
The galvanic Cell:
Self sustaining electrode reactions
Conversion of electrical energy into chemical
energy
LESSON
- 1 (C)
DATE COMPLETED:
Learners will be TAUGHT and LEARN the following:
To define the galvanic cell in terms:
LESSON OBJECTIVES
o
Definition of Redox Reaction – in relation to electron (e-) transfer.
o
The importance redox reactions in relation to energy conversion.
o
The application of these reactions in electrochemical cell of torch cells, car battery, etc.
2.
LESSON OUTCOMES – At the end of the lesson learners should be able to:

define what is galvanic cell, using oxidation and reduction (electron (e-) transfer)

describe when the substance is anode and when the substance is cathode.

describe galvanic cell as self sustaining electrode reactions

understand conversion of electrical energy into chemical energy
Term 2 Page 81
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
TEACHER ACTIVITIES
1.
LEARNER ACTIVITIES
TIMING
Baseline Assessment:
2.1 Introduction
The galvanic cell represented in the diagram below consists of a
Mg electrode dipped into a Mg(NO3)2 solution, and a Pb
electrode dipped into a Pb(NO3)2 solution. Assume that the cell
operates under standard conditions
a) Pre-knowledge required.
1.

NEEDED
TEACHING METHODS USED IN THIS LESSON:
Explanations, illustrations, Demonstrations and questions and answer
methods
2.
RESOURCES
Lesson Development
The teacher will introduce the lesson by giving learners baseline
assessment.
State TWO standard conditions in which the cell operate.
(temperature 25 0C, Concentration 1 mol·dm-3)
Worksheet
± ( 15 min)
e-
V
OR
Baseline
assessment:
RECAP QUESTION: TEST KNOWLDGE
1.1 A standard voltaic cell is set up using a Ni | Ni2+ electrode as the
positive electrode. The cell has emf of 2, 12 V.
1.1.1
Identify the negative electrode. Show all workings
EMF = EΘ(cell) = EΘcathode - EΘanode
Half-cell A
Half-cell B
2, 12 = - 0, 25 - EΘ anode
1.1.2
= - 2, 37 V (magnesium)
2.
Write down the half – reaction that takes place in half- cell
A. (Mg(s) → Mg2+(aq) + 2e-)
Write down oxidizing agent in this cell.
Ni2+(aq)
3.
Write down the cell notation of this cell.
2+
-3
2+
Feedback: provide
correct answers
-3
Mg(s) | Mg ( 1mol·dm ) || Pb (s) (1 mol·dm ) | Pb (s)
Discussion and Explanation Method (the teacher will clear any
misconceptions that the learners may have)

Facilitate group discussion/ Response from the above assessment
activities.
4.
Chalkboard
summary
± ( 15 min)
Calculate the EMF of this cell.
EMF = EΘ(cell) = EΘcathode - EΘanode
= - 0, 13 – (-2, 36)
= 2, 23 volts
Term 2 Page 82
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

Explain the concepts:
5.
How will each of the following changes influences the value
EMF calculated above, WRITE only decrease increase or
stays the same?
-
In this section we investigated the indirect transfer of electrons
using an electrochemical cell.
-
The investigation clearly illustrates how chemical energy is
converted into electrical energy.
Decrease
-
Galvanic cell is another type of electrochemical cells.
5.2 An increase in the concentration of [Pb 2+(aq)]
-
We refer to this as indirect transfer of electrons.
Increase
2
Lesson development
6.
5.1 An increase in the concentration of [Mg 2+(aq)]
2.1 Contextualization questions:
In which direction from Half – Cell A to B, or Half – cell B to A
do cations move within the salt bridge to maintain electrical
neutrality? Explain how you arrived at your answer
Explanation
The teacher will facilitate these question with the learners allow them to
discuss their solutions in class (± 10 minutes can be spend)
Half cell A to Half cell B

Concentration of positive ions / cations / Pb ions decreases in
half-cell B. /
2+
In industry, the use of electrochemical processes such as
electroplating and the manufacture of certain chemicals such as
liquid bleach are important.
OR/OF

In our homes and offices we make use of batteries to power our
radios, torches, laptops and toys.
These batteries operate as electrochemical cell
± 15 minutes
Charts/ or
available
resources
OR
2+

Demonstration and
Concentration of positive ions / cations/Mg ions increase in
half- cell A.
• To prevent a build-up of positive ions in half-cell A and
negative ions in half-cell B / For electrical neutrality, positive
ions migrate from/through the salt bridge.
1.
GROUP WORK ACTIVITY
Learners will work in groups to find solutions:
Identification of the precipitate formed during the discoloration
of the copper sulphate solution.
1.2 Write down and balance a reaction of Hydrochloric acid
reacting with zinc, liberating hydrogen. Show the phases of the
substances.
Zn(s) + 2HCl(aq)
Term 2 Page 83
→
ZnCl2(aq)
+
H2(g)
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
INSTRUCTIO
ONS AND DEMONSTTRATION:
-
Consider two half-cells c
connected by a sa
alt bridge.
-
nction of the salt b
bridge will be mad
de clearer shortly.
The fun
-
In the c
cell on the left, a silver electrode is dipping
d
into a silve
er nitrate
solution
n (AgNO3 (aq).
-
The cell on the right has a copper electrod
de dipped into a c
copper
nitrate solution (Cu(NO3)2).
-
A cond
ducting wire connects the two electrodes to each other.
-
The following reaction ta
ake place
2. Write down the reaction of Nitric acid reacting
r
with copp
per.
What iss the colour solutio
on?
3 Cu(s)) + 8 HNO3 (aq) → 3 Cu(NO3)2 (aq
q) + 4 H2O (l) + 2 NO
(g)
11. From the previous sec
ction, it appears that a reaction occurs
when zzinc metal Zn (s) comes into contac
ct with copper ionss
Cu2+ (a
aq). However, if co
opper is placed in
n a solution containing
zinc ion
ns
Illustration
ns and
Explanatio
on
± 15 – 20 minutes
m
1.1.1 Is there any reactio
on taking place?
No rea
action takes place
e.
evant
Rele
equiipments/ or
othe
er available
reso
ources.
1.1.2 W
Write down the equ
uation which desc
cribes your assump
ption.
V
electron flow
Cu (s)
+
Zn2+ (aq) → no reaction
salt bridge
1.1.3 Is this reaction spon
ntaneous or not sp
pontaneous explaiining
your an
nswer?
Cathode
Zn
Cu
-
anode
NO 3
NO-3 3
Ag+
1.1.4 W
Write down the equ
uation that indicates reaction betw
ween
zinc me
etal when it come
es in contact with copper solution.
+
Cu2
Ag+ (aq) + e-
→ Ag (s) and Cu (s)
Zn (s) + Cu2+ (aq) → Zn2+ (aq) + Cu (s)
→ Cu2+ (aq)
+ 2e-
DISCUSSION
N
-
The silver ions are reduce
ed to produce silver atoms.
-
The copper atoms are oxxidised to copper ions.
-
Electrons travel from the anode through th
he conducting wirre to the
cathod
de.
Not spo
ontaneous, having
g to change external factors to startt the
reactio
on.
1.1.5 Is this reaction spon
ntaneous or non sp
pontaneous expla
ain
your an
nswer?
Sponta
aneous reaction, ta
akes place withou
ut having to chang
ge
any ex
xternal factors to sttart the reaction
Since tthis sort of reaction
n finds wide applic
cation in a study of
o
electro
ochemical cells, it is important to kno
ow which reaction
ns
Term 2 Page 84
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
-
These electrons are accepted by the silver ions which are then
reduced to form silver atoms.
What happens in each of the solutions in each half cell
-
between metals and metal ions actually lead to spontaneous
reactions.
In this connection, carry out the following investigation
In the copper half cell, the solution around the electrode is
surrounded by Cu2+ ions.
-
To maintain the neutrality of the solution, negative ions are
Lesson
Demonstration
required.
-
Similarly in the silver half cell, the solution surrounding the electrode
± 15 minutes
contains the negative ions (NO3-)
-
In order to maintain the neutrality in this half cell, positive ions are
required.
-
The function of the salt bridge is to facilitate movement of negative
and positive ions from solution of each half cell, thus preventing the
build up of space charge around each electrode.
-
-
The construction of salt bridge is such that it allows for the
Chalkboard
summary
Practical Investigation:
(The practical can be done after the complete of the lesson)
Students will perform practical experiments of Zinc/Copper
electrochemical cell.
movement of ions through it.
Cell consists of two half cells each containing a solution of
CuSO4 and ZnSO4 respectively.
The salt bridge is filled with an electrolytic solution such as KNO3 or
-
The concentration of each solution is 1 mol.dm-3.
-
A salt bridge (usually KNO3 or KCl) complete the circuit.
-
When the switch is closed, the ammeter registers a current,
indicating electron flow through the connecting wire.
KCl and is plugged at each end by porous plugs.
Learners will work in groups to find solutions:
Solutions to this practical will be presented by groups to class.
CONCLUSION:

A reducing agent is a substance which, during a reaction, acts as
an electron donor and is oxidised in the process.
Term 2 Page 85
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

A oxidizing agent is a substance which, during a reaction, acts as
an electron receiver and is reduced in the process.

Galvanic cells are self sustaining electrode cells.

Electrodes are immersed in the electrolyte solution of separate
beakers.

Salt bridge compete the external circuit of this reactions.

Energy is converted from chemical to electrical energy
Reflection/note
Name of Teacher
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 86
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Electrochemical Reactions:
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
18
TOPIC
o
The electrolytic cell:

Electrode reactions that are sustained by a
supply of electrical energy.
Conversion of electrical energy into
chemical energy
LESSON
2
DATE COMPLETED:
1.
Learners will be TAUGHT and LEARN the following:
o
To define the electrolytic cell in terms of

Electrode reactions that are sustained by supply of electrical energy

Conversion of electrical into chemical energy.
o
Relation of current and potential to rate and equilibrium.
2.
LESSON OUTCOMES – At the end of the lesson learners should be able to:

define what is an electrolytic cell in terms of electrode reactions that are sustained by supply of electrical energy.

What energy conversion takes place in this cell?

What is the relationship between current and potential to rate and equilibrium?

To write down anode half-reactions and the cathode half-reaction.

To indicate positive and negative terminal of electrode when connected to a battery
TEACHER ACTIVITIES
LEARNER ACTIVITIES
TIMING
RESOURCES NEEDED
1. TEACHING METHODS USED IN THIS LESSON:
Explanations, illustrations, Demonstrations and questions and answer methods
Baseline Assessment:
2. Lesson Development
a) What form of energy is found in the battery?
Term 2 Page 87
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.1 Introduction

a) Pre-knowledge required.
b) What form of energy is found in ionic
solution?

The teacher will introduce the lesson by giving learners baseline assessment.

OR
Electrical energy
Chemical energy

Using question and answer method recap from previous knowledge?
c) Mention the components of a complete
external circuit.

Facilitate group discussion/ Response from the activity


Demonstration – to introduce the concepts
‐
Prepare the practical investigation of galvanic cell.

Explanation – Oxidation and Reduction and half cell reactions

The teacher should ask questions: One word item, multiple choice questions
and longer questions.
Facilitate group discussion/ Response from the above assessment activities.
Explain: Anode and Cathode electrodes
Lesson development
3.1 Contextualization questions:

What form of energy is found in this cell?
± ( 15 min)
Battery, conductors, switch, resistors and
ammeter
d) What is the unit of the physical quantity
potential difference of the battery?

Volts
e) Which elements will bond together in order
to form table salt.
Discussion and Explanation Method (the teacher will clear any misconceptions that
the learners may have)


3.
Worksheet
Baseline
assessment:

Sodium (Na) and Chlorine (Cl2)
1.
GROUP WORK ACTIVITY
Feedback:
provide correct
answers
± ( 15 min)
Chalkboard
summary
Learners will work in groups to find solutions:
1.
GROUP WORK ACTIVITY
Learners will work in groups
+
battery
-
A
Q
P
CuSO4 (aq)
Demonstration
and
Explanation
± 15 minutes
Term 2 Page 88
Charts/ or available
resources
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
1.
Define the term electrolysis.
OR
Decomposition reaction of molten or aqueous
solution by an electric current. Electrical energy is
converted into chemical energy.
2.
Fuel Cell
Fuel cells consist of an anode and a cathode, separated by an ionic conductor
electrolyte. The electrons generated at the anode move through an external
circuit containing the load and pass to the cathode. Fuel, commonly hydrogen,
ammonia, or hydrazine, is supplied to the anode, while an oxidant, commonly air
or oxygen, is
supplied to the cathode. Ions generated at the cathode are conducted by the
electrolyte to the anode, where they form water by combining with hydrogen.
© Microsoft Corporation. All Rights Reserved.
4.
Which electrode, P or Q, consists of the im
copper? Explain how you arrived at your
answer.
P = positive electrode (anode) because
oxidation takes place at the positive elect
anode.
3.
Lesson Presentation
Write down the half-reaction that takes pla
electrode Q.
Cu2+ (aq)
4.
+ 2 e-
→
Cu (s)
During purification, metals such as silver and Illustrations and
platinum form sludge at the bottom of the Explanation
container.
± 15 – 20 minutes
Refer to the relative strengths of reducing a
to explain why these two metals do not form
during the purification process.
Relevant
equipments/ or other
available resources.
Pt and Ag are both weaker reducing agent
copper and will not be oxidised, Copper is
strong reducing agent.
Term 2 Page 89
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
5.
EXPLANATION:
‐
Non – spontaneous reaction is taking place.
‐
The chemical process happening in an electrolytic cell called electrolysis.
‐
Electricity in the form of direct current passes through a solution containing ions
resulting in chemical changes at the electrode.
‐
Metals and Non – Metals are decomposed into two ions
‐
Metal ions are positive as metals lose negative electrons
‐
Non-metal ions are negative as non-metals gain negative electrons
VIDEO SHOW/ USING A CHART TO EXPLAIN ELECTROLYTIC CELLS
+
battery
The rate at which copper is oxidised at the
anode is equal to the rate at which copper
ions are reduced at the cathode.
6.
Why is the sludge of economic importance
Contains valuable/ expensive metals.
Platinum and Silver are valuable/ expensive
metals
HOME WORK
A
Q
P
Explain why the concentration of the copper
(II) sulphate solution remains constant.
Assume that the only impurities in the copper
are silver and platinum.
Electroplating is one of the uses of electrolysis.
The diagram below shows an electrolytic cell that
can be used to plate a copper spoon with silver.
CuCl2 (aq)
Copper
Spoon
Lesson
Demonstration
Chalkboard
summary
± 15 minutes
Electrode
AgNO3
Term 2 Page 90
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
1.
DEMONSTRA
ATION:
An electrode is a conductor through which
w
electrical cu
urrent enters or
lea
aves the conductin
ng medium.
‐
Ad
direct current batttery is connected to two inert graph
hite electrodes (th
hat
do not react with the
e electrolyte or with the products off electrolysis).
‐
‐
e electrodes are d
dipped into a moltten copper (II)chlo
oride electrolyte.
The
‐
The
e molten CuCl2 de
ecomposes or breaks up into positiv
ve ions (cations) an
nd
neg
gative ions (anion
ns)
The prrocess in which electrons
e
are
lost or given off by a sub
bstance.
2.
CuC
Cl2
→ Cu2+
+ 2 Cl -
+
- ons
ani
Cations
s
Cu
4.
Cu
Cl
Cu
Cu2+
+
2 e- → Cu
Cl
Cl
2Cl -
→
Cl2
+ 2 e-

ve ions are attractted to the negativ
ve electrode
Positiv

gains electrons
and g

ode half reaction
Catho

ode
Copper metal is deposiited on this electro
Write down a half-reaction that
explains the change tha
at occurs on
the su
urface of the copper spoon
during
g electrolysis.
Ag+ (a
aq) + e-
+
-
What type of half-rea
action takes
place at the copper spoon? Write
only
OXIDATION
down
or
REDUC
CTION.
Reduc
ction
3.
-
Define
e the term oxidattion in terms
of elec
ctron transfer.
→ Ag (s)
+
Name
e the metal thatt is labelled
'electrrode'.
+
Silver/
/ Ag
5.
a
reason
Give
why
w
the
entration of the AgNO
A
conce
3(aq)
during
remain
ns
constant
electro
olysis.
The ra
ate of oxidation
n of (Ag)
equalss the rate of red
duction (of
Ag+)
Term 2 Page 91
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Electrodes are reversed compared to a battery

2Cl -
→
Cl2
+ 2 e-

Negative ions are attracted to the positive electrode

And lose electrons

Anode half reactions

Chlorine gas is formed at this electrode
TEACHING – ACTIVITY
1.
Prepare a worksheet to describe half cell reactions of copper and chlorine.
2.
Learners should describe cathode and anode in this cell.
3.
Describe the direction in which electrons are moving.
4.
What energy conversion would take place?
5.
What do we understand by inert electrodes ?
6.
What colour is the copper that is deposited onto the electrode?
CONCLUSION:

Electrical energy is converted into chemical energy.

Cathode is the negative electrode and anode is positive electrode.
The reaction is non- spontaneous.
BIBLIOGRAPHY
‐
Children Encarta – 2008 encyclopaedia
‐
GDE exam papers.
‐
Learner Work book – Watson Duncan
Term 2 Page 92
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 93
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Electrochemical Reactions:
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
18
TOPIC
o
Relation of current and potential to
rate and equilibrium

Give and explain the relationship
between current in an
electrochemical cell and the rate
of the reaction.
State that the pd of the cell (Vcell)
is related to the extend to which
the spontaneous cell reaction has
reached equilibrium
State and use the qualitative
relation between Vcell and the
concentration of product ions and
reactant ions for the spontaneous
reaction.

LESSON
3
DATE COMPLETED:
1.
Learners will be TAUGHT and LEARN the following:-
o
Relationship between current in an electrochemical cell and the rate of reaction
o
State that the pd of the cell (Vcell) relate spontaneous reaction reached equilibrium
o
State relationship Vcell and the concentration of product ions and reactant ions
o
Effect of the concentration of solution on Vcell
2.
LESSON OUTCOMES – At the end of the lesson learners should be able to:

Explain how the rate of reaction affects the current that is produced by electrochemical reaction.

What is the Pd (Vcell) of the cell in relation to their spontaneous reaction?

Explain how the concentration of ions affect reaction rate of the cell.

Explain the concept of battery when “Flat”.
Term 2 Page 94
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

Describe when battery is in equilibrium and draw the graphs.

State and use the qualitative relation between Vcell and the concentration of product ions and reactant ions for the spontaneous reaction.
TEACHER ACTIVITIES
1.
LEARNER ACTIVITIES
Baseline Assessment:
Define the concept “current”?
‐
Lesson Development

Flow of charges/ ions in a solution
2.1 Introduction
Describe the reaction that is spontaneous?
‐
a) Pre-knowledge required.


The teacher will introduce the lesson by giving learners baseline
assessment.
Energy of the solution is enough to keep it
working
‐
OR

Using question and answer method recap from previous
knowledge?

Facilitate group discussion/ Response from the activity

Demonstration – to introduce the concepts
‐
Explanation – Oxidation and Reduction and half cell reactions

The teacher should ask questions: One word item, multiple
choice questions and longer questions.
Discussion and Explanation Method (the teacher will clear any
misconceptions that the learners may have)




Baseline assessment:
± ( 15 min)
What instruments is used to measure the
potential difference of the cell?
Explain the difference between closed
and open circuit?
Closed circuit – when the current flows in a
circuit by closing the switch
Feedback: provide
correct answers
Chalkboard summary
± ( 15 min)
Open circuit – when no current is flowing by
the opening of switch
‐

Worksheet
Voltmeter
‐
Prepare the practical investigation of galvanic cell.


RESOURCES NEEDED
TEACHING METHODS USED IN THIS LESSON:
Explanations, illustrations, Demonstrations and questions and answer
methods
2.
TIMING
What unit is the strength of solution
measured in?
Mol· dm-3
Facilitate group discussion/ Response from the above
assessment activities.
Explain: Equilibrium, Potential difference, use EΘ table,
Term 2 Page 95
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
3. Lesson development
EXPLANATION:
Demonstration and
Explanation
- The rate of reaction depends upon current in the galvanic Cell.
± 15 minutes
- Current is maximum to begin with and decreases as the
concentration of the reactants get used up.
- The reaction at the surface of the electrodes produce a
e-
Zn electrode
Cu electrode
e-
blue
OR
e-
e-
e-
Charts/ or available
resources
+
1.
e-
Learners will work in groups to find solutions:
GROUP WORK ACTIVITY
2.
Zn2+
Cu2+
GROUP WORK ACTIVITY
‐

Zinc metals will be coated with copper metal
- Within the cell, current is carried by the flow of ions.
‐
- To maintain electrical neutrality, positive and negative ions must be
able to cross the boundary between the two half-cells.

- When the battery is fully charged, we say the battery is in
equilibrium, there is no noticeable current through a battery.
- As reactants are used up and more products form, the increasing
reverse reaction starts opposing the decreasing forward reaction,
causing the EMF to decrease relative to standard conditions.
- When one of the reactants is almost used up, there is no more
noticeable current and we say the battery is in equilibrium. It is “flat”.
Judging from your observation, is the
reaction spontaneous or non-spontaneous?
spontaneous
‐

What caused the blue colour of the
solution?
Cu2+ ions in a solution
‐

Predict what will happen when Zn metal is
immersed in CuSO4 solution.
What is colour change of the solution as the
reaction takes place?
The blue colour become clear/ disappear
Illustrations and
Explanation
Relevant equipments/ or
other available resources.
± 15 – 20 minutes
Term 2 Page 96
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Practical Demonstration
3. Lesson Presentation
TEACHING – ACTIVITY
- Learners will prepare a solution of copper
sulphate in glass beaker
rate
rate of reactants being used up
rate of products forming
- Immerse zinc metal in the solution and observe
what reaction is taking place
Equilibrium
Chalkboard summary
time
REDOX REACTION
Cu2+ (aq)
+
Zn (s)
Reactants
Zn 2+ (aq)
+
Products
Cu (s)
HOMEWORK
Lesson Demonstration
1.1 The Zn is (oxidised/ reduced) as it (gains/loses)
electrons.
± 15 minutes
1.2 The electrons lost by Zn are transferred to the
Cu2+ ions.
1.3 The Cu2+ is (oxidised/ reduced) as it (gains/
loses).
Use electrode potential table:
DL: Table
1.4 What gives the colour of the copper solution
blue?

Cu2+ ions
1.5 Write down half cell reaction that occurs on
zinc.

Zn
→ Zn2+ + 2 e-
1.6 How can we get the Zinc half-reaction and the
copper half-reaction to release their stored up
chemical energy as thermal energy. How do
we observe this?
Term 2 Page 97
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
CONCLUSION:

Oxidation and Reduction occurs simultaneously

When the battery is to be “flat”, reaction rate has reached
equilibrium.
Electrons flow from negative electrode to positive electrode
Reflection/note
Name of Teacher
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 98
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Electrochemical Reactions:
GRADE
12
SUBJECT
Physical Sciences
WEEK
18
TOPIC
o
Understanding of the processes and redox reaction
taking place in the cell.


Movement ions through the solutions.
The electron flow in the external circuit of the cell
and
Their relation to the half reactions at the electrodes
The function of the salt bridge.

LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
4
DATE COMPLETED:
1.
Learners will be TAUGHT and LEARN the following:
o
Understanding of the processes and redox reaction taking place in the cell.

Movement ions through the solutions.

The electron flow in the external circuit of the cell and

Their relation to the half reactions at the electrodes

The function of the salt bridge.
2.
LESSON OUTCOMES – At the end of the lesson learners should be able to:

Describe movement of ions through the solutions,

Identify cations and anions in the cell.

State the functions of the salt bridge.

The type of salt found in the salt bridge.

To indicate positive and negative terminal of electrode when connected to a battery
TEACHER ACTIVITIES
1.
LESSON
TEACHING METHODS USED IN THIS LESSON:
Explanations, illustrations, Demonstrations and questions and answer methods
LEARNER ACTIVITIES
TIMING
RESOURCES NEEDED
Baseline Assessment:
Individual Work:
- An ion is : charged atom or group of
Term 2 Page 99
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.
Lesson Development
atoms
2.1 Introduction
- An anion is : A negatively charged ion
a) Pre-knowledge required.
- cation is: A positively charged ion

The teacher will introduce the lesson by giving learners baseline assessment.

OR
Using question and answer method recap from previous knowledge?
- OILRIG stands for: Oxidation is the loss
of electrons, reduction is the gain of
electrons

Facilitate group discussion/ Response from the activity

Demonstration – to introduce the concepts
‐
Prepare the practical investigation of galvanic cell.

Explanation – movement of ions in a solution

The teacher should ask questions: One word item, multiple choice questions
and longer questions.
Worksheet
Baseline assessment:
± ( 15 min)
- LEO stands for : Loss of electrons is
oxidation
- GER stands for : Gain of electrons is
reduction
Feedback: provide
correct answers
Chalkboard summary
± ( 15 min)
Discussion and Explanation Method (the teacher will clear any misconceptions
that the learners may have)

Facilitate group discussion/ Response from the above assessment activities.
1. FACILITATE GROUP DISCUSSIONS
Find the EMF of the following
electrochemical cells under standard
conditions
Ba
and
Sn:
EΘ Sn - EΘ Ba = - 0, 14 – (- 2, 9) = 2, 76 V
Ca
and
Mn:
EΘ Mn - EΘ Ca = - 1, 18 – (- 2,87) = 1, 69
V
Co
and
Ag:
Term 2 Page 100
Demonstration and
Explanation
± 15 minutes
OR
Charts/ or available
resources
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Lesson development
EΘ Ag - EΘ Co = +0, 8 – (- 2, 08) = 1, 08 V
Movement of ions through the solution:


Positive ions (cations) will move in the same direction (from anode - negative
Zn
and
Cu:
to cathode - positive).
EΘ Cu - EΘ Zn = + 0, 34 – (-0,76) = 1, 1 V
The Cu2+ ions move towards the copper plate, attracted by the electrons
that have flowed from the Zn plate

The positive charge in the cathode solution thus gets less.
Mg and
Pb:

In response to this charge imbalance, the K+ ions in the salt bridge migrate
EΘ Pb - EΘ Mg = - 0, 13 – (-2, 37) = 2, 24 V
into the cathode solution to replace the
Missing positive charge and thus keep the solution neutral.
Zn2+

The Zn dissolves and the

This increases the concentration of Zn2+ ions in the anode solution and the
ions entre the solution near the Zn electrode.
positive charge thus build up.

To maintain the neutrality, the excess Zn2+ ions migrate into the salt bridge.

The electrons left by the dissolving zinc, remain on the Zn plate. As this
negative charge builds up it repels the electrons through the wire towards

GROUP WORK
The cell notation of a standard galvanic
(voltaic) cell containing an unknown
metal electrode X is shown below.
3)
X(s) | X3+(1 mol·dm-3) || Pb2+(1 mol·dm| Pb(s)
that have flowed from the Zn plate in the external circuit.
1.1 Name the component of the cell
represented by the double
vertical lines (||) in the above cell
notation.
The positive charge in the cathode solution thus gets less. The negative
Answer: Salt bridge
the Cu electrode. These electrons then attracted the Cu2+ ions.

1.
The Cu2+ ions move towards the copper plate, attracted by the electrons
sulphate ions in the cathode solution migrate into the salt bridge to get rid of
the excess negative charge.
Function of the salt bridge: (symbol //)
1.
The salt bridge maintains the electrical neutrality of the half cell solutions.
2.
The salt bridge connects the two solutions and completes the circuit.
3.
The salt bridge replace the imbalance of ions keep the two solutions neutral
1.2 State the TWO standard conditions
that are applicable to the Pb2+/Pb
half-cell.
Illustrations and
Explanation
± 15 – 20 minutes
Relevant equipments/
or other available
resources.
Answer: Concentration of the electrolyte
– 1 mol·dm-3 and Temperature of 250C/
298 K
1.3 Identify the oxidising agent in the
Term 2 Page 101
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
4.
The voltmeter between the two will now read 1 V, the two half-cells form a full
cell (battery).
The standard conditions under which standard electrode potentials are
determined
1.
These values were measured at 250C (101,3 kPa)
2.
Using the concentration of 1 mol·dm-3
These values are indicated by symbol Θ. (it used to be EΘ)
above cell.
Answer: Pb2+/ lead (II) ions
1.4 The initial reading on a voltmeter
connected across the electrodes of
the above cell is 1,53 V. Identify
metal X by calculating the standard
reduction potential of the unknown
metal X.
Answer:
CONCLUSION:
EΘ cell = EΘ cathode - EΘ anode

Positive ions from the salt bridge balance the solutions
1, 53

Electron will flow from negative pole to positive of the cell

Zn dissolves and the Zn2+ ions enter the solution
EΘ = -1, 66 V, unknown metal X is
aluminium

Zn electrode loses mass as it dissolves.

Cu electrode gains mass as Cu atoms deposit on it.
BIBLIOGRAPHY:
‐
Learner work book: Duncan Watson
‐
Power point presentation – physical science
= (- 0, 13) - EΘ anode
1.5 Write down the balanced equation
for the net (overall) reaction taking
place in this cell. Omit the spectator
ions.
Answer: 2 Al (s) + 3 Pb2+ (aq) → 2Al3+
(aq) + 3 Pb (s)
1.6 How will the initial voltmeter reading
be affected if the concentration of
the electrolyte in the X(s)|X3+(aq)
half-cell is increased? Write down
only INCREASES, DECREASES or
REMAINS THE SAME.
Lesson Demonstration
± 15 minutes
Chalkboard summary
Answer: Decrease
Term 2 Page 102
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
1.7 Write down the value of the reading
on the voltmeter when the cell
reaction has reached equilibrium.
Answer: 0 V
Reflection/note
Name of Teacher
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 103
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Electrochemical Reactions:
GRADE
12
SUBJECT
Physical Sciences
WEEK
LESSON SUMMARY FOR: DATE STARTED:
1.
19
TOPIC

o
o
o
Standard Electrode potential:
Standard hydrogen electrode
Use the table of standard reduction potentials
Positive value indicates spontaneous under
standard conditions
Lesson
1
DATE COMPLETED:
Learners will be TAUGHT and LEARN the following:
To describe: the standard hydrogen electrode and explain its role as the reference electrode.
Explain how standard electrode potentials can be determined using the reference electrode
Use the table of standard reduction potentials to deduce the emf of a standard galvanic cell
Use positive value of the standard emf as an indication that the reaction is spontaneous under standard conditions.
LESSON OBJECTIVES
LESSON OUTCOMES – At the end of the lesson learners should be able to:

To describe: the standard hydrogen electrode and explain its role as the reference electrode.

Explain how standard electrode potentials can be determined using the reference electrode

Use the table of standard reduction potentials to deduce the emf of a standard galvanic cell

Use positive value of the standard emf as an indication that the reaction is spontaneous under standard conditions.
TEACHER ACTIVITIES
1.
TIMING
RESOURCES
NEEDED
TEACHING METHODS USED IN THIS LESSON:
Explanations, illustrations, Demonstrations and questions and answer
methods
2.
LEARNER ACTIVITIES
Lesson Development
Baseline Assessment:
Individual Work:
1.1 What instruments is used to measure electrical potential?
2.1 Introduction
Answer: voltmeter
a) Pre-knowledge required.
1.2 Define the concepts Oxidation and Reduction.
Term 2 Page 104
Baseline assessment:
Worksheet
± ( 15 min)
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans


The teacher will introduce the lesson by giving learners baseline
assessment.
OR
Using question and answer method recap from previous
knowledge?
Answer: Oxidation – loss of electrons by a substance
Reduction – gain of electrons by a substance
1.3 What is an electrolyte?

Facilitate group discussion/ Response from the activity
Answer: a pure substance that is an electrical conductor due to
the movement of ions when it is in solution.

Demonstration – to introduce the concepts
1.4 Why is a metal electrode necessary in a half-cell?
‐
Prepare the practical investigation of galvanic cell.
Zn
→ Zn2+
+
Explanation – Oxidation and Reduction and half cell reactions
Answer: it acts as an electrical conductor

The teacher should ask questions: One word item, multiple
choice questions and longer questions.
1.5 Why is this anode?


3.
Facilitate group discussion/ Response from the above assessment
activities.
Explain: Anode and Cathode electrode
Lesson development
± ( 15 min)
Chalkboard
summary
2e-

Discussion and Explanation Method (the teacher will clear any
misconceptions that the learners may have)
Feedback: provide
correct answers
Answer: Oxidation occurs at the anode
1.6 The Zn atoms are (oxidised/ reduced) as it (gains/ loses)
electrons.
GROUP WORK ACTIVITY
1.1 Describe the external circuit of the galvanic cell.
Answer: It is the wire connecting the two electrodes plus any
electrical device that is connected to this wire. A flow of
electrons occurs in the external circuit from anode to cathode.
Demonstration and
Explanation
± 15 minutes
COMPARE COPPER AND HYDROGEN ELECTRODE
2
Learners WILL draw and label a sketch
Term 2 Page 105
OR
Charts/ or
available
resources
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
A simple fo
orm of hydrogen electrode
HOMEWORK
H2 (g)
[ H+ (aq)]
Pt (metal)
3. Lesson D
Development
1.
Label all the missing arrows.
a
2.
Nam
me the type of ele
ectrochemical celll that converts
che
emical energy to electrical
e
energy.
3.1 Contex
xtualization questio
ons:

When m
measuring height, we usually say the ground level is zzero.

In Geography, sea level is chosen as the zero
z
height.

Hydrog
gen half- cell is cho
osen as the standa
ard with zero pote
ential
4.
Lesso
on Presentation
Answer: Galvanic Cell
3.
e electrochemica
al cell is set up as illustrated, there wiill
If the
be n
no reading on the voltmeter. Give a reason for this
obse
ervation.
e down the value of the standard emf
e
of the
Write
elec
ctrochemical cell when
w
it is function
ning.
4.
- The poten
ntial difference be
etween a metal an
nd a solution of the
e
metals ions is called the meta
al electrode poten
ntial.
Answer: 0, 76 V
- Platinum sshows no tendenc
cy to dissolve.
5.
- The standard electrode cho
osen is the hydrog
gen electrode.
± 15 – 20 minutes
Answer: Incomplete circu
uit/ No salt bridge
EXPLANATIO
ON:
- It adsorbs [sic] Hydrogen on
nto its surface as siingle atoms and b
brings
them into c
close contact with
h their dissolved ion
ns, H+ (aq).
Illustrations and
n
Explanation
vant
Relev
equip
pments/ or
other available
resou
urces.
Write
e down the voltmeter reading when the net cell
reac
ction in the above
e electrochemical cell reaches
equ
uilibrium.
Answer: Zero
Term 2 Page 106
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
- The standard hydrogen halff-cell has a standa
ard electrode pote
ential,
EΘ, defined as 0, 00 volts.
6.
c
be compared
d to the
- The electrrode potentials of other chemicals can
hydrogen e
electrode potentia
al.
Answer: Zn (s)
- A voltmete
er is used to meassure the electrode
e of the other meta
als
relative to h
hydrogen electrod
de if all standard conditions
c
are
considered
d.
o
All ionic
c solutions must be
e at a concentratiion of
o
Any ga
as involved must b
be at a pressure off
(atmosspheric pressure).
1 mol ·dm
m-3
o
Platinum
m must be used a
as the electrode when
w
the half-cell ssystem
does not include a meta
al.
25 0 C (298
8 K)
Comparing
g zinc and hydroge
en electrode pote
ential
eKCl
H2(g)
Zn
n
Pt
H+
2e-
Whic
ch electrode will undergo
u
a decrea
ase in mass? Give a
reasson for your answe
er.
Mg, because magnessium is oxidised
Calc
culate the initial emf of this electroc
chemical cell at
stan
ndard conditions.
Afte
er a while the emf of this electrochemical cell
dec
creases. Explain thiis observation by referring
r
to the
concentration of the electrolytes.
Lesson Dem
monstration
Answer:
As the c
cell functions, the concentration
c
of zinc
z
ions (reactantts)
decreasses relative to stan
ndard conditions and the
concenttration of magnesiium ions (productss) increases relativ
ve
to standard conditions . The reverse reactiion starts opposing
g
the forw
ward reaction caussing the emf to dec
crease relative to
standard
d conditions.
Salt bridge
Zn
+
Answer: EΘ (cell) = EΘ (oxidising agent) - EΘ(reduucing agent)
= - 0, 76
7 - ( - 2, 6)
= + 1, 6 V
9.
TEACHING – ACTIVITY
e-
7.
8.
All subsstances must be a
at a temperature of
o
→ Zn2+
Anotherr electrochemical cell is set up unde
er standard
conditio
ons by replacing th
he standard hydro
ogen half-cell with a
standard
d magnesium halff-cell.
101, 3 kPa
o
e down the equation for the reactio
on that occurs at the
Write
ano
ode.
2+
(aq)
Zn2 +(aq)
± 15 minutess
Challkboard
summ
mary
10. Elec
ctrochemical cells such as motor ca
ar batteries with
plasstic casings can ha
arm the environme
ent if not disposed
d of
safe
ely. Suggest TWO ways
w
how motor car
c batteries can be
b
safe
ely disposed of.
Answer:
Neutralisse acid before dissposal/ • Recycle plastic casing and
d
lead ele
ectrodes/
Term 2 Page 107
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
o
0, 000 volt assigned to the hydrogen.
o
– 0, 76 V for Zn2 +│Zn is called the relative standard potential.
o
Cell notation: Pt, H2 (gas) │ H+(aq) ││ Zn 2+(aq) │ Zn (s)
o
Solid double lines indicates salt bridge
o
Customary: the hydrogen electrode is always written on the left
o
The potential of the cell is defined as:
ѳ
E
cell
= EΘcathode - EΘanode / EΘcell = EΘreduction - EΘoxidation
CONCLUSION:

The standard hydrogen electrode is used to determine the
electrode potential of the other electrodes.

Positive reading, it indicates that the electrons are moving from
the hydrogen electrode to the other electrode.

Negative reading, it indicates that the hydrogen electrode is now
the cathode (reduction) occurs.
Electrons flow from negative electrode to positive electrode
Term 2 Page 108
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 109
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Electrochemical Reactions:
o

GRADE
12
SUBJECT
Physical Sciences
WEEK
19
TOPIC



LESSON SUMMARY FOR: DATE STARTED:
1.
o




Writing of equations representing oxidation
and reduction half cell reactions and redox
reactions
Predict the half-cell in which oxidation will take
place.
Predict the half cell in which reduction will take
place.
Write equations for reactions taking place at
the anode and cathode.
Deduce the overall cell reaction by combing
two half-reaction
Lesson
2
DATE COMPLETED:
Learners will be TAUGHT and LEARN the following:
Writing of equations representing oxidation and reduction half cell reactions and redox reactions
Predict the half-cell in which oxidation will take place.
Predict the half cell in which reduction will take place.
Write equations for reactions taking place at the anode and cathode.
Deduce the overall cell reaction by combing two half-reaction
LESSON OBJECTIVES
2. LESSON OUTCOMES – At the end of the lesson learners should be able to:




Predict the half-cell in which oxidation will take place.
Predict the half cell in which reduction will take place.
Write equations for reactions taking place at the anode and cathode.
Deduce the overall cell reaction by combing two half-reaction
TEACHER ACTIVITIES
1.
LEARNER ACTIVITIES
TIMING
RESOURCES
NEEDED
TEACHING METHODS USED IN THIS LESSON:
Explanations, illustrations, Demonstrations and questions and answer
methods
Baseline Assessment:
One word question
Term 2 Page 110
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.
Lesson Development
1.
2.1 Introduction
a) Pre-knowledge required.

The teacher will introduce the lesson by giving learners baseline
assessment.
A substance that shows a decrease in oxidation
number during chemical reaction.
Oxidizing agent
2.
Baseline assessment:
The electrode in an electrochemical cell where
oxidation occurs.
Worksheet
± ( 15 min)
Anode.

OR
Using question and answer method recap from previous knowledge?

Facilitate group discussion/ Response from the activity

Demonstration – to introduce the concepts
‐
Prepare the practical investigation of galvanic cell.

Explanation – concepts
Cell X:
CuCl2 (aq)

The teacher should ask questions: One word item, multiple choice
questions and longer questions.
Cell Y:
Zn(s) + CuSO4 (aq) → Cu (s) + ZnSO4 (aq)
3.
The unit in which EΘ is measured. Volts
Multiple Choice:
1.
The reactions below occur in two different
electrochemical cells X and Y.
Feedback: provide
correct answers
± ( 15 min)
Chalkboard
summary
→ Cu (s) + Cl2 (g)
Discussion and Explanation Method (the teacher will clear any
misconceptions that the learners may have)
3. Lesson development
Cell X
Cell Y
A
Cl2 (g)
Cu (s)
B
Cu (s)
Cu (s)
C
Cl2 (g)
ZnSO4 (aq)
D
Cu (s)
ZnSO4 (aq)
VIDEO SHOW/ USING A CHART TO EXPLAIN GALVANIC CELLS
Voltaic Cell: A Chemical Battery
Term 2 Page 111
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
DEMONSTRATION AND PREDICTIONS:
Answer: B
‐
Oxidation (loss of e-) will take place at an anode.
‐
Reduction (gain of e-) will take place at a cathode.
‐
Anode is the negative electrode
‐
Cathode is the positive electrode.
‐
A half reaction represents either oxidation only or reduction only.
‐
Represent: Zn │ Zn2+ half cell or Cu│ Cu2+ half cell
From the
‐
EΘ
+
2 e- ⇌ Cu
+ 0, 34 V
Zn2+
+
2 e- ⇌ Zn
- 0, 76 V
+
-0, 76 V (Anode)
→
Zn2+
Cu2+
+ 2e-
→
Which ONE of the following statements regarding the
anode of a standard galvanic cell in operation is
correct?
A. The anode accepts electrons.
B. The mass of the anode decreases.
C. The concentration of the electrolyte in the half-cell
containing the anode initially decreases.
D. The anode is the positive terminal of the cell.
Answer: B
3.
Table:
Cu2+
Zn
2.
2e-
Cu
+0, 34 V (Cathode)
_________________________________________________
Zn
+
Cu2+
→
Zn2+
+
Cu
Overall Cell:
The double arrow ⇌ means each half cell could either gain
or lose electrons, depending on what other half – cell
it is connected to.
Half Reaction of Copper:
‐
Cu 2+ is positive about gaining electrons, so the
forward reaction is favoured.
Cu 2+
+
2 e- → Cu
Demonstration and
Explanation
± 15 minutes
Charts/ or
available
resources
OR
When the net (overall) cell
reaction in a galvanic
(voltaic)
cell
reaches
equilibrium, the emf of the
cell is equal to ...
A
+2,00 V.
B
+1,00 V.
C
0,00 V.
D
-1,00 V.
Answer: C
1.
GROUP WORK
The diagram below represents a galvanic (voltaic) cell
functioning under standard conditions with magnesium and
silver as electrodes. A voltmeter connected across the
electrodes shows an initial reading of 3,17 V
+ 0, 34 V
Cu 2+ gains 2 electrons to form Cu (s).
Illustrations and
Explanation
Cu 2+ is reduced and is thus the cathode.
± 15 – 20 minutes
Term 2 Page 112
Relevant
equipments/ or
other available
resources.
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
V
Half Reaction of Zinc:
‐
Mg
salt
Zn is negative about gaining electrons, so the reverse reaction is
favoured.
2+
Zn 2+
+
2 e- ← Zn
- 0, 76 V
You may not write it like this thus correctly written:
Zn
→
Zn2+
+ 2 e-
- 0, 76 V
‐
Zn loses 2 electrons to form Zn 2+ (aq)
‐
Zn is oxidised and is thus the anode
Mg2+(a

Positive ions from the salt bridge balance the solutions

Electron will flow from negative pole to positive of the cell

Zn dissolves and the Zn2+ ions enter the solution

Zn electrode loses mass as it dissolves.

Cu electrode gains mass as Cu atoms deposit on it.
SOLUTION TO GROUP WORK ACTIVITY:
Ag+
4.1
State the energy conversion
that takes place in this cell.
4.2
State
TWO
standard
conditions under which this
cell operates.
4.3
Identify the anode of this
cell. Refer to the relative
strength of reducing agents
to explain how you arrived
at the answer.
4.4
Write down the cell notation
(symbolic notation) of this
cell.
4.5
Write down the balanced
equation for the net (overall)
cell reaction that takes
place in this cell. Omit the
spectator ions.
CONCLUSION:
4.1 Chemical (potential) energy to electrical (potential) energy.
4.2 Temperature = 25 0C /298 K.
Ag
Concentration of electrolytes = 1 mol·dm-3
4.3 Magnesium / Mg
Magnesium is a stronger reducing agent, (than Ag)
therefore Mg will be oxidised/;lose electrons.
Term 2 Page 113
Lesson Demonstration
Chalkboard
summary
± 15 minutes
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
4.4
Mg | Mg2+ (1 mol·dm-3) || Ag+ (mol·dm-3) | Ag
OR
Mg | Mg2+ || Ag+ | Ag
OR
Mg(s) | Mg2+ (aq) || Ag+ (aq | Ag(s)
4.6
How will an increase in the
concentration of the Ag+ ions
influence the current that the cell
delivers?
Write
down
only
INCREASES, DECREASES or REMAINS
THE SAME and explain the answer.
4.5 Mg + 2Ag+ Mg2+ + 2Ag bal
4.6 Increases. (Or any equivalent word)
The rate of the forward reaction increases (when [Ag+] increases.) /
Tendency for the reaction to proceed from left to right increases.
More electrons are released per unit time.
BIBLIOGARPHY:
‐
Children Encarta – 2008
‐
GDE question paper – 2011
‐
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 114
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
Electrolytic Reactions:

GRADE
12
SUBJECT
Physical Sciences
WEEK
19
TOPIC
o
o
LESSON SUMMARY FOR: DATE STARTED:
LESSON OBJECTIVES
1.
Learners will be TAUGHT and LEARN the following:

Describe, using half equations and the equation for the overall cell reaction,
o
The decomposition of copper chloride
o
A simple example of electroplating (e.g. the refining copper)

The concept electr oplating of metals

The coating a metal (eg. iron) with another metal (eg. tin) because tin has a more useful property of not rusting

Electroplating depends on current strength, concentration, temperature, distance between electrodes and surface preparation

The use of this technique to purify copper
2.
LESSON OUTCOMES – At the end of the lesson learners should be able to:


write down half cell reaction for electroplating
give examples of metals that do not oxidise easily.
•
identify the compound that must be used as the anode or the cathode during electroplating.
3
LEARNER ACTIVITIES
TIMING
RESOURCES
NEEDED
TEACHING METHODS USED IN THIS LESSON:
Explanations, illustrations, Demonstrations and questions and answer
methods
2.
Lesson
DATE COMPLETED:
TEACHER ACTIVITIES
1.
Describe, using half equations and the
equation for the overall cell reaction,
The decomposition of copper chloride
A simple example of electroplating (e.g.
the refining copper)
Lesson Development
Baseline Assessment:
Individual Work:
1. Define the concept oxidation of metals.
Term 2 Page 115
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
2.1 Introduction
Answer: Loss of electrons by metals
a) Pre-knowledge required.
2.

Non – Metals: Cannot conduct electricity
Baseline assessment:
Metals: conduct electricity
± ( 15 min)

The teacher will introduce the lesson by giving learners baseline
assessment.
OR
Using question and answer method recap from previous
knowledge?

Facilitate group discussion/ Response from the activity

Demonstration – to introduce the concepts
‐
Prepare the practical investigation of galvanic cell.

Explanation – concepts

The teacher should ask questions: One word item, multiple
choice questions and longer questions.
3.
Worksheet
Chemical formula: Silver Nitrate and Potassium Cyanide
Answer: AgNo3 and KCN
4.
Mention products that are used daily in households that are
plated.
Answer: Teapot, Knife
5. What energy conversion takes place when electroplating?
Feedback: provide
correct answers
± ( 15 min)
Chalkboard
summary
Answer: Electrical energy is converted to chemical energy
Discussion and Explanation Method (the teacher will clear any
misconceptions that the learners may have)
GROUP WORK ACTIVITY
a.
3. Lesson development
An attractive silver appearance can be created by electroplating
artefacts made from cheaper metals, such as nickel, with silver. The
simplified diagram below represents an arrangement that can be
used to electroplate a nickel artefact with silver
Electrolyte Y
Electrode X
Nickel artefact
solution
The properties of metals and non – metals.
b.
c.
Ag+
d.
e.
Ag +
Which electrode (cathode/anode) will the nickel artefact
represent?
Name the metal represented by electrode Y. (Silver)
Write down the half-reaction responsible for the change that
occurs at the surface of the artefact.
+
e-
→ Ag
Give a reason why the concentration of the electrolyte
remains constant during electroplating.
The rate of oxidation of silver at the anode is equal to the rate
of reduction of silver ion at the cathode
In industry some plastic articles are sometimes electroplated.
Explain why plastic must be coated with graphite before
electroplating.
Plastic is a non-conductor, graphite is a conductor
Term 2 Page 116
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
1.
Which electrode (cathod
de/anode) will the
e nickel artefact
represe
ent?
f. Give a rreason why, from a business point of view, it is not
advisable
e to plate platinum
m with silver.
Demonstrattion and
Explanation
n
2.
Name the metal represe
ented by electrod
de Y.
Platinum iis expensive, more
e durable than oth
her metals.
± 15 minute
es
3.
Write d
down the half-reac
ction responsible for
f the change that
occurs at the surface of the artefact.
4.
Give a reason why the c
concentration of th
he electrolyte rem
mains
constant during electrop
plating.
HOMEWO
ORK ACTIVITY
5.
ustry some plastic a
articles are sometimes electroplated.
In indu
Explain
n why plastic must be coated with graphite
g
before
electro
oplating.
The diagra
am below represe
ents a cell that can
n be used to
electropla
ate a tin medal with a thin layer of silver
s
to improve itss
appearan
nce.
Cha
arts/ or
ava
ailable
reso
ources
OR
S
6.
Give a reason why, from
m a business point of view, it is not
advisab
ble to plate platin
num with silver.
3.
Lesson Development
p
2.2 Contex
xtualization questio
ons:
ME
EDAL
1.
Electroplatiing
Teapots are
e electroplated w
with a thin layer of silver
s
to protect th
hem
from corrossion and to give th
hem an attractive finish. Objects tha
at are
electroplatted are first cleane
ed, and then plac
ced in a bath thatt
contains ions, or positively ch
harged atoms, of the
t
metal that will be
deposited o
on them. The obje
ect to be plated iss connected to the
e
negative end of an electric c
current source, wh
hich causes the ob
bject
to attract th
he positive metal ions in the bath.
Which
h one of P or the MEDAL
M
is the anod
de in this cell?
Answer: P
wn the following:
Write dow
2.
NAME
E or SYMBOL of the
e element of whic
ch electrode P is
comp
posed. Answer: Ag
g/ Silver
Illustrations and
Explanation
n
± 15 – 20 minutes
Term 2 Page 117
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
3. Lesson Presentation
3.
EXPLNATION:
‐
‐
Electroplating: is used to protect metals that oxidise very easily
by covering them with a thin layer of a metal that does not
oxidise easily.
NAME or FORMULA of the electrolyte that has to be used to
achieve the desired results.
Answer: Silver Nitrate/ AgNO3 or silver ethanoate/
acetate/ CH3COOAg
4.
The metal object that must be plated, acts as the
Relevant
equipments/ or
other available
resources.
Switch S is now closed. Write down the visible changes that
will occur at the following:
4.1 Electrode P:
‐
cathode (negative electrode) and must be always be
connected to the negative terminal of the electrical supply.
‐
It is suspended into a bath that contains a solution of a suitable
salt of the metal with which it is suppose to be plated.
‐
‐
Answer: Silver/metal bar becomes
eroded/pitted/smaller/thinner, eaten away
4.2 The medal:
5
The electrolyte is a mixture of silver nitrate and potassium
cyanide.
The cyanide ensures that the concentration of the silver ions,
required for plating, are of good quality
6
ELECTROLYTE, ANODE AND CATHODE
Ag (s)
→
Ag + (aq)
Ag +
Ag +(aq)
+
+
+
NO -3 (aq)
e-
→
e+
(anode)
H2O (in electrolyte solution)
Ag (s) (cathode)
- Anode is made of an impure metal and the same metal – when
deposited on the cathode – is absolutely pure.
7
Answer: A (silver) layer forms on medal
Write down the equation for the half-reaction to support the
answer to QUESTION
Answer: Ag+ + e- → Ag
How will the concentration of the electrolyte change during
the electroplating process? Write down only INCREASES,
DECREASES or REMAINS THE SAME.
Answer: Remain the same
You want to coat the medal with copper instead of silver.
State TWO changes that you will make to the above cell to
obtain a medal coated with copper.
Answer: Replace the silver solution with copper solution/
soluble copper salt
- Vast quantities of copper are purified by electrolysis with impure
copper slabs as anodes and thin sheets of pure copper as
cathodes.
- During the electrolysis copper (II) ions leave the anode slabs and
plate out on the cathode sheets when they are discharged.
Term 2 Page 118
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans
BIBLIOGRA
APHY
TEACHING – ACTIVITY
e
ve
negativ
pure copp
per
electrode
-
positive
impure cop
pper
- Children
n Encarta – 2008 (R
Robert Harding pic
cture library).
electrode
e
+
Lesson Dem
monstration
± 15 minute
es
Cha
alkboard
sum
mmary
- Exam qu
uestion paper – 20
008
- Oxford SSuccessful – Physic
cal Sciences (Pete
er Broster et al)
+
-
+
-
+
copper sulp
phate solution

The mo
ost important use o
of electroplating:
- The anod
de made of an im
mpure metal and th
he same metal-wh
hen
deposited o
on the cathode – is absolutely pure
e.
- Vast quantities of copper a
are purified by electrolysis with impu
ure
bs as anodes and thin sheets of purre copper as cathode.
copper slab
- The electtrolyte is a solution of copper sulpha
ate
CuSO4 (aq)
e electrolysis copp
per (II) ions leaves the anode slabs a
and
- During the
plate out o
on the cathode she
eets when they arre discharged.
- Less reactive metals such a
as gold, silver and platinum form a m
mud
under the a
anode and more rreactive metals su
uch as zinc remain
n as
ions in the ssolution. In effect tthe reaction are: Cu (s) → Cu2+ (aq) →
Cu (s)
CONCLUSIO
ON:

Electroplating is used to protect metals tha
at oxidise very eassily

um cyanide are used
u
as mixtures
Silver nitrate and potassiu
Term 2 Page 119
© Gauteng Department of Education (ver.1)
Grade 12 Physical Sciences Lesson Plans

Source current is required in order to conduct this process

Reduction takes place at the negative cathode

Oxidation takes place at the positive anode

Electrolytic cells use a lot of energy. Power stations burn coal to
produce this energy and as a result huge quantities of carbon
dioxide are produced. This contributes to an increase in the
greenhouse gas emissions and thus an increase in global
warming.
Reflection/note
Name of Teacher:
HOD:
Sign:
Sign:
Date:
Date:
Term 2 Page 120
© Gauteng Department of Education (ver.1)